Jackson Shuttleworth: Why streaks are Duolingos growth lever

1. 0:00 – 6:00

   Jackson’s background and an overview of Duolingo’s streak feature

   1. SPSpeaker0:00

      (instrumental music) ... Duolingo is a 14 billion company. It's hitting all-time highs, too. It just keeps going up. I think it doubled in value in the past six months. Streaks is the most impactful feature.

   2. SPSpeaker0:08

      We have, right now, over nine million users with a year-plus streak. If you look at the numbers, I think this has been our biggest growth lever. And what Duolingo really focuses on is, you know, how do we help users build habits around language learning? Getting a user to come back the next day is the biggest problem to solve.

   3. SPSpeaker0:24

      Well, let's get into the mother lode (laughs) of learnings from the journey of Streaks, talk about the key lessons, insights, and also where it turns along the way.

   4. SPSpeaker0:30

      I'd say, like, test everything. We have run, in the last four years, over 600 experiments on the Streaks, so every other day. We've actually set up really good infrastructure for copy testing. We used to say, "Continue." Our, like, standard CTA is Continue. And we changed that to "Commit to my goal," and it was, like, a massive win.

   5. SPSpeaker0:48

      There's so much human psychology that you all learn through all these experiments of just, like, how to motivate people, what motivates, what demotivates.

   6. SPSpeaker0:55

      ... say that you played a mobile game or that you've done it for 3,000 days in a row, I don't know, maybe that hits a little bit different than you've learned Spanish for 3,000 days in a row. (graphics whooshing)

   7. SPSpeaker1:07

      (instrumental music) Today, my guest is Jackson Shuttleworth. Jackson is a group product manager at Duolingo, leading the retention team. This is a different kind of episode that I'm experimenting with, where we spend the entire conversation focused on the journey and lessons of a single feature, in this case, Duolingo Streaks. Duolingo is a $14 billion business. Just over the past six months, they doubled in value. They're hitting all-time highs in usage and market cap. They're also one of the very few successful, and also the single biggest, consumer app business in the world. And as you'll hear from Jackson, the Streaks feature is the single most impactful feature that most contributed to this growth and success. In other words, you could argue this one feature created billions of dollars of value, which, to me, means it is worth studying in-depth. In our conversation, Jackson shares the history of the Streaks feature, all of the biggest wins and wrong turns they've taken along the way, what he and his team have learned about what works and doesn't work with the Streaks mechanic, and also how they set up their teams to operate in a way that allows them to run over 600 experiments on this product and continue to find big wins. I hope to do more episodes like this on features and products that you'd love to hear more about. So, leave a comment, either on YouTube or on Substack, and tell me which product or feature you'd love to see me cover. And if you enjoy this podcast, don't forget to subscribe and follow it in your favorite podcasting app or YouTube. It's the best way to avoid missing future episodes, and it helps the podcast tremendously. With that, I bring you Jackson Shuttleworth. Jackson, thank you so much for being here, and welcome to the podcast.

   8. SPSpeaker2:48

      Yeah, thank you. Longtime listener, first-time caller, so...

   9. SPSpeaker2:51

      (laughs) I appreciate it. So, this is gonna be a really interesting conversation. I've never done an episode like this before, where we basically spend like an hour, an hour and a half, going into one feature of one product. But this is a very special feature, it's a very special product. Um, have you ever spent like an hour, an hour and a half just talking about this one (laughs) feature with anyone?

   10. SPSpeaker3:13

       No- well, internally, so when we, when we onboard new folks to the team, we'll do, I actually just did this with somebody that joined the team recently, where we spent, and I was like, "Hey, let's spend an hour just talking about this Streak." We got through an hour and I got through about 30% of, of what I, I, I wanted to share. Um, there's just so much. We'll talk about this, but there's so much that we've learned over the years. Uh, but never anything externally like this. I think we've shared bits and pieces of learnings, but this'll be like the, the mother lode of learnings, hopefully-

   11. SPSpeaker3:40

       (laughs) Here we go.

   12. SPSpeaker3:41

       ... uh, of, of how Duolingo has built the Streak.

   13. SPSpeaker3:42

       We should title this "The Motherlode of Learnings-"

   14. SPSpeaker3:44

       (laughs)

   15. SPSpeaker3:44

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2. 6:00 – 9:58

   The impact of streaks on Duolingo’s success

   1. SPSpeaker6:00

      slash Lenny.Okay. So for people that don't know anything about what Duolingo streaks are, can you just first give a brief explanation of what is Duolingo streaks? What is this feature all about?

   2. SPSpeaker6:10

      Well, presumably people know, uh, Duolingo is a language learning app. Um, the, the Duolingo streak tracks currently anyway, how many days in a row you've done a lesson. So you come to do a lingo, you do a lesson. Your first lesson, you know, you'll start a streak and then every consecutive day that you come, use the app, you'll extend your streak. And, and I should actually put an asterisk around how many days in a row, because we also have built flexibility into the features. So we have these things called streak freezes, it's like insurance for your streak. So, you know, it's pretty simple feature, you know, in, in theory, but over time we've layered on challenges and goal setting and rewards and, you know, social features. You know, a lot of our notifications are tied to the streak. So pretty simple feature to understand, but it's been a really rich feature for us to, to build on top of.

   3. SPSpeaker6:58

      Some people might be hearing this be like, "Duolingo streaks, like what's the big deal?" There's other people that are like, "Holy shit, I want to learn everything I can possibly learn about Duolingo streaks." So many companies are trying to copy what you've learned from this. Give people a sense of the impact that this one feature has had on Duolingo's success and growth.

   4. SPSpeaker7:14

      This is... And, and this is not just the, you know, subjective retention PM talking. I think this is our biggest feature at D- Uh, with the exception of the lessons. And I think it's actually worth start that, like streaks are a great engagement hack. I'm kind of, of the opinion that any team, you know, any app out there can introduce a streak and if you figure it out, it probably works, um, you know, to retain users. But at the core, like you have to have an app that people want to use. And people really like using Duolingo, it's fun, it's delightful, you learn something. And so it allows us to layer an engagement mechanic on, on top of that. Like the streak is really powerful. So it ships a disgusting amount of DAUs. Again, it is just... It is, it is our, um, one of our golden geese. And, and again, what's cool is that like, you know, you look at notifications. Notifications for Duolingo is massive. I mean, you know, us sending better, you know, whether it's copy or timing. So many of our notifications work because they reference the streak, because users care about the streak. And so not only is it itself, us iterating on the streak, a huge driver of DAUs, but it's also something that enables other really high, you know, valuable features. I was looking up some stats before I came on and it's pretty crazy. So we have right now over nine million users with a year plus streak.

   5. SPSpeaker8:30

      Wow.

   6. SPSpeaker8:30

      So nine million of our users have had, uh, used Duolingo every or almost every day for, uh, you know, well over a year. Um, which, which is pretty, which is, it, it's... I don't know, it's... I like to imagine things in terms of like, you know, okay, well, like if you put all these people in a city or, you know, in a place where would it be and like, ah, it's like a very large city, nine million people. So...

   7. SPSpeaker8:53

      For a year, have been-

   8. SPSpeaker8:54

      Per year.

   9. SPSpeaker8:54

      ... have a yearlong streak. That's incredible. I was just looking at the, the stock of Duolingo. So Duolingo is a 14-billion-dollar company at the time we're recording this. It's hitting all-time highs too. It's like just keeps going up. I think it doubled in value in the past six months, something like that. And what I'm hearing from you is streaks is this... Other than just like the core learning feature, which is just like the product of Duolingo, this is the most impactful feature in terms of growth and in that retention specifically.

   10. SPSpeaker9:24

       I mean, if you look at the numbers, I think pretty objectively has been our biggest growth lever for, for driving DAUs. And, and also say a lot of it's just related to how we think about growth at Duolingo. And a lot of what we try to do is organic growth. You know, we think about growth, you know, just as much as bringing new users onto the platform is not losing them. If you're just bringing people onto the platform then they churn, that's not gonna be sustainable. And so as much as we can do to keep our users coming back and actually retaining as users, it's gonna make it... It's gonna give us a much easier base to continue growing DAUs off of.

   11. SPSpeaker9:57

       Perfect. Okay.

3. 9:58 – 14:50

   The origin and evolution of streaks

   1. SPSpeaker9:59

      Talk about how this feature originally came to be. What was the original version of it? What was the original insight that led to B1?

   2. SPSpeaker10:04

      Yeah. So the oldest streaks are as old as Duolingo itself. We, when we launched Duolingo, we, we launched with the streak. And I say we, I was like just graduating undergrad when, when Duolingo launched. Um, so this is well before my time. Um, but we launched with a streak feature. The... You know, the... Initially h- how the, how the feature worked was you'd come to Duolingo and you'd set a goal for yourself. Um, and it was an XP-based goal. So Duolingo, a little bit of like, you know, nomenclature, we have a experience point space system that drives a lot of our features in the app. And the way you'd set it is you'd say, you know, based on what your language learning goal was, you know, may- maybe have a 10 experience point goal versus a 50 experience point goal. And so extending your streak would be, "Hey, can you hit 50 experience points," if that's what you set your goal to be. And this worked well. I think this also speaks to like how Duolingo initially grew. You know, we were... Luis launched it with a TED Talk, you know, we probably had a more tech-forward user base, you know, initially. And so this whole idea of like an experience point space streak system made sense. But what that also meant is that you could have a user come and use the app, do multiple lessons a day, and maybe they just set too hard of a goal for themselves and then lose their streak, which I, I don't... You know, you don't need to be an expert in streaks to understand that's, that's probably not good. You know, the nice thing with how we initially set it up though is it really did connect with what your goal was. So if you were serious, let's track how good you are at being a serious language learner. But I'd say one of the most impactful experiments we ran was about f- This was actually as I was joining, we had... Or, or just after I'd joined, we'd, we had run this experiment, um, was to move it from a XP-based streak to just do one lesson a day and you'd extend your streak. And, and you know the risk that you can sort of imagine as well then users kind of care less about it 'cause it's not connected with their goal. And we saw none of that. I mean, this was huge driver of DAUs just making it, making it easier to extend your streak, but I think really importantly is still meaningful, right? Like the unit of use, and: you know, as you're thinking about building a streak, like I think it's really important to think about like what the unit of use of your app is.Um, the unit of use for Duolingo is, like, doing a lesson. And so, if what we care about is users coming back every day and doing a lesson, 'cause it shows that they're actually engaging with the app, then it doesn't hurt us to make our streak focus on just do one unit versus multiple. And so that was, like, probably the big sea change experiment that we ran, um, you know, at the time, was moving from an XP-based streak to a one lesson streak. It's also simple. And, and I think that's, like-

   3. SPSpeaker12:32

      Yeah.

   4. SPSpeaker12:32

      ... one of the things to think about with streaks. It's always easy as a PM to, like, over... You know, have a million goals or objectives for what you want your feature to be and, and potentially build a more complex feature. In a one lesson streak, it's just easy for more users to understand.

   5. SPSpeaker12:46

      Yeah. That's exactly what I was gonna say, and just for folks that aren't super familiar with XP, it's basically experience points, and you get them from, like, doing things. It's like a Yeah, you do, you do stuff on Duolingo, and then based on what you did and how well you did it, we give you experience points. This actually drives a number of our features in our app. So leaderboards is the big one. You know, we have a leaderboard system where you try over the course of the week, you battle with 29 other people, and y- y- you wanna win. That's all driven by XP. So we do have other features in the app that really benefit from this XP system. Cool.

   6. SPSpeaker13:16

      The streak is just no longer one of them.

   7. SPSpeaker13:18

      Awesome. Okay, so I want to talk about the journey from that point to what it is today. But a quick tangent, I saw Luis tweet just this week. Someone asked him, "How do you decide whether to optimize for learning or engagement?" And he's like, "No question. Uh, everything we do is focused on engagement because you won't learn anything if you're not coming back to the app."

   8. SPSpeaker13:39

      As an engagement PM, that was like-

   9. SPSpeaker13:41

      (laughs)

   10. SPSpeaker13:41

       ... the coolest thing he could have ever said. It's... Well, again, very much as a, you know, object- uh, subjectively, I guess, as a engagement PM, I mean that's how I've... You know, I, I'm sure my learning, the, the learning folks at Duolingo will cringe when they hear it. Like, I see myself as a learning PM as much as an engagement PM, because the easiest way not to learn on Duolingo is not to come back the next day. And so if we don't make the app retentive, you will have no opportunity to engage with our learning features. Now, I do think that there is a long tail of learning, where if you start to dumb down... And honestly, this is, this is something we, we wrestle with at Streak as well, you start to dumb down the experience and your users aren't actually learning, they're not going to care. I mean, Streak's works best when they're sitting on top of an app, you know, uh, that, that users care about. Um, but yeah, I mean, if, if you can't come... You know, if you don't come learn on Duolingo... You know, if you don't come back to Duolingo, then you're not learning, so... Um, now, we... I mean, we track a lot of this with, you know, the work that we do, we make sure that as we're making changes to the streak, we're not hurting the learning experience, and we don't have a ton of interaction with it, so we're constantly thinking about this. But thank you, Luis, for saying that.

   11. SPSpeaker14:47

       (laughs) It makes sense to me.

4. 14:50 – 24:38

   Key experiments and insights

   1. SPSpeaker14:50

      Okay, so let's get into the mother lode of learnings from the journey of Streaks. So the first version went from XP to one lesson. Talk about the key lessons, insights, and also wrong turns along the way to what we see today.

   2. SPSpeaker15:03

      Duolingo has very much... Uh, you know, has a, has a strong, like, test-it philosophy. Um, you know, we're willing to test a lot of different... Honestly, we'd much rather test it than, like, debate it for, you know, days and days. So we actually followed up this experiment with... And this was, this was a little bit later, with, "Hey, what if we make it even easier to extend your streak?" And so we actually tested, hey, if you, if you do one exercise, just one exercise in a lesson, we'll, we'll extend your streak. And, and, and a lot of, like, the insight was good. Like, you look at the funnel. Hey, there's a lot of users who are starting but not finishing lessons, they're not extending their streak, the loss aversion doesn't kick in, they don't, you know, come back. So this kind of followed that train of thought. What we realized when we ran this experiment is, um, you know, DAUs mo- moved not one bit. And, and what we would, what we were doing by... And this, if we go back to, like, unit of measure, you know, we had, we had dumbed down the unit of... And nobody thinks about, "Oh, I just wanna come, you do one question on Duolingo." Nobody thinks about that. Um, so we had more, like, a, a, a less clear unit of measure that we were basing our streak around. And, and the users that we are capturing with our streak, you know, you come, you do one or two questions on Duolingo, then you leave, were, like, the least engaged users imaginable. And so, you know, I think that's something also to think about as you're building your streak, is, like, what is the user that you're solving for? So not only what is the kind of habit that you're building for, but, like, what is the level of commitment? And that was an example where we overindexed on a type of user who we honestly just weren't going to keep. Uh, that was a very easy shutdown, uh, shutdown decision.

   3. SPSpeaker16:39

      That's an awesome story. I just, just to comment on that real quick, just, like, you went... Like, "Let's just go to the extreme and make it just, like, streaks. Yeah, get everyone going streaks forever." And then I love that it turned out no, this... It's not bringing users that you want, and it's dumbing down the experience. Makes me think of FarmVille where you have to go and, like, harvest your crops every whatever hour (laughs) and just, like... Like, that lasts for a bit, and then eventually people are like, "What the hell am I doing with my life?"

   4. SPSpeaker17:03

      Yeah, exactly. No, we... I mean, and we test every... So we... I was looking at the numbers as well. We've, we've run, in the last four years, over 600 experiments on the streak. So every other day, effectively-

   5. SPSpeaker17:14

      600? Wow.

   6. SPSpeaker17:15

      ... we're running an experiment. And, and they range from big, like this, like, changing how the mechanic works, to, like, let's swap a string with another string and see if that copy is better, you know, for, for users. So, so we're constantly testing on, on everything. I do think that, like, I'd be more careful running that experiment now. Like, at some point, your streak gets big enough that... Again, I got nine million users on the streak, I gotta be really care- those are our best retaining users, you know? You kinda gotta be careful. But in the early days of the streak, I'd say, like, test everything. I mean, see what... Don't get, don't get super caught up in, "It has to be like this." Just test a bunch of stuff and see what speaks most to users. 'Cause I, I think, you know, again, you will constantly be surprised by the, the insights that you get from whether you... We, we shut down about half of our experiments, so half of our big expe- uh, of our experiments lose. We still learn a ton by virtue of, of running them, so super, super valuable.

   7. SPSpeaker18:08

      That's actually a good success rate. Uh, a lot of companies have only 20%, uh-

   8. SPSpeaker18:12

      Mm-hmm.

   9. SPSpeaker18:12

      ... experiments be positive. What's your policy on is if it, if it's neutral, do you ship it or do you kill it?

   10. SPSpeaker18:18

       It really depends. If, if we're adding something and it's, and it's neutral, we tend to, to, to shut it down because it's just more cognitive load, it's something that we're gonna have to start building around, a new UI element that we have to figure out how it fits into our system. I'd say when we do ship a neutral experiment is something that, that we have real, uh, conviction around, "Okay, yeah, maybe this was neutral, but it's gonna give us a new platform to then build on top of." So that experience might be neutral, but now we can build these DAU-positive experiments. And my general take there is though, in that case, build that in as part of your V1 so that it, you know, you make sure that, like, at least your hypothesis around this roadmap, you know, has play, you know, should probably be the case. But in general, shutting down a neutral experiment so you don't introduce more complexity to the app is, is, is the way we tend to go.

   11. SPSpeaker19:10

       Makes sense. All right. What else? What else have you learned along the journey?

   12. SPSpeaker19:13

       Well, I mean, maybe I can talk about a few different ways that we structure... Uh, you know, I, a, a few different themes that I think we, we, we lean on. Um, so the first is focusing on the zero to seven day user experience. And I would say this is, if you look at the kind of, uh, you know, what our breakdown of experiments are, we run definitely more than average number of experiments on getting users to go from a zero to seven day streak. Um, and a lot of this is because we've looked at the data for, you know, our retention curves, and what we found is that once you get to seven days, loss aversion kicks in and, and, and you retain. So going from a one to a two day streak, huge jump in retention. Two to three day streak, slightly less, but still huge. And it's up until day seven. Once you hit day seven, it flattens out. And it's not to say that, like, you know, if you're a, you have a 30-day streak, you're way more attentive than day seven, but not in the order of magnitude that it is from, from day one through seven. So we do a ton of work to get users to that point where loss aversion kicks in, and then they don't want to, um, they don't want to leave the app. Uh, one of the fun ones that we did, and it's, it's honestly as much about process as it is about the feature itself, was, um, we have a feature called Streak Goal. And it is... Again, so much of this stuff seems so obvious in retrospect, um, but, you know, it was really novel at the time. You know, we, we had this idea of like, "Hey, maybe we'll just goal users to hitting a certain streak length." As you can imagine, this is pretty powerful, uh, you know, user psychology. Um, and we started with the simplest version of this, and this is how Duolingo does a lot of our testing. You know, rather than design the big complex feature for V1, just do, like, the simplest encapsulation of what that feature can be, see if it has legs, and then just add to it iteratively over time. This is partially how we get to, you know, 600 plus experiments on streaks. They're not all big ones. But we started, and it was funny, we actually took our learning from our monetization team. So one of the strings that they had, the pieces of copy that they had worked really, really well was, I think it was, "You're, like, 5.6 times more likely to finish the course if you subscribe to Plus." And so our, you know, now it's Super, our, our subscription. And it was, it was a really good hook that if you, if you really cared you'd sign up. Um, and so we ran a similar... We, we, we had a similar thought where it's like, "Oh, let's just tell you how much more likely you are to finish the course if you get a 30-day streak." And so we started with that, and I think it was like, "You're seven times more likely to finish the course if you have a 30-day streak." And just that message, when you started your streak, us telling you that was (blows raspberry) awesome, huge win. Um, you know, indicating an outcome... And, like, Duolingo doesn't ha-... Like, we don't... We have a gem economy, but we don't actually have, like... You know, it's just, it's, it's all you learning. But being able to actually talk about it in terms of the outcomes that a user would think about, in this case, trying to finish the course, was a huge win. So this is where we started, and we're like, "Ah, goal setting. All right, we, (laughs) we should go much harder on this."

   13. SPSpeaker22:06

       Found some, found a...

   14. SPSpeaker22:07

       Yeah, we found one thing, and now let's just beat the heck out of it.

   15. SPSpeaker22:10

       Yeah.

   16. SPSpeaker22:10

       Um, so we followed that up with another experiment where we, we tested different lengths. So we'd test 14 days and then 50 days, and we found that they were all good, but they, they, uh, uh, appealed to different users. And so we started to realize, "All right, well, we probably need to be more thoughtful about who we give, you know, these different options to." And, and, and so then we followed that experiment up with, "All right, let's start with 30 days, and then we're gonna let you opt out." You know, we'll, we'll say, "No, I don't think I can hit it." And our thinking was, "And then if you say no, we'll hit you with an easier goal," 'cause we just wanted to get you to commit to a goal. And (laughs) this was a fascinating one because it was a good win to give users that easier goal to try to captures- capture them before they said no, but it was almost just as big a win to add that opt out button. So we tested separately, and I'm a huge fan of testing, like, way too many arms for an experiment just to, like, be able to isolate your hypotheses. But, but we captured, you know, just what happens if we add an opt out button. And adding an opt out button... And you would think, like, as a PM, "Oh, I'm like, you know, now users might not engage with my feature. That's a bad thing." But it was a huge win to let them do that. And, and the learning here was that this intentionality of saying, "No, I want..." Previously, it was just a Continue button, but now it's like, "No, I want to hit 30 days." And, and, and having that be an intentional decision for them, yes or no, even though, again, this had no impact. None o- Or, or no impact past this screen. Uh, everything that I'm talking about now was, uh, you know, just that screen that day, and then was all thrown out. So that optionality was, was, was, uh, you know, a huge insight. And so because of that, we built a, a goal setting feature where you could choose between different goals. Giving users that optionality was, was, uh, likewise a huge win. I'll say one, one final learning on this. Um, again, you talk about, like, friction and, and good and bad friction. We thought once we built a, you know, a, a goal picker screen where you could pick between different streak lengths, we, we were like, "Oh, well, let's, like, recommend that users do a hard, you know, a harder goal," and thinking that, "Okay, well a harder goal is gonna be better retention." And, and we'll pre-select the harder goal for them.And this, based on all the learnings that I just shared with you, you can probably imagine, lost pretty significantly. We realized that, like, yes, we could speed users through the screen more by virtue of picking a goal for them. But, like, that act of selecting, I think it's 30 days, I think it's 14 days-

   17. SPSpeaker24:36

       Mm-hmm.

   18. SPSpeaker24:36

       ... was where we were getting so

5. 24:38 – 28:36

   User psychology and engagement strategies

   1. SPSpeaker24:38

      much of the engagement from this feature.

   2. SPSpeaker24:39

      There's so much human psychology (clears throat) that you all learn through all these experiments, of just, like, how to motivate people, what motivates, what demotivates. Feels like you guys should write a book on human psychology and motivation.

   3. SPSpeaker24:51

      I, I feel very much like a amateur armchair psychologist with everything that... At, at least as far as people who want to learn languages on their phone go.

   4. SPSpeaker25:01

      Right, right.

   5. SPSpeaker25:01

      Like, I, I really understand those folks.

   6. SPSpeaker25:03

      So one (clears throat) one kind of theme I'm hearing here so far is you guys are basically just, like, mining for gold, just, like, looking for, like, a vein in some mine, and once you hit it, you're like, "Ooh, this worked." You just go crazy on just testing all kinds of things to see if you, how far you can take that one little i- thread.

   7. SPSpeaker25:22

      Yeah, and I think, you know, I, I, I shared that, that the, how this idea came partially from, you know, a monetization win that they had. I think there's a lot of, you know, because Duolingo runs... I, you know, I don't know what percentile we're in, but it's gotta be a very high percentile of, you know, per capita experiments run for a company, you know, based on company size. We're just constantly learning so many things, and there's a really great cross-sharing of monetization say, "Hey, this thing worked for us. Is that something you can use?" So I, I'd say it's rare that we go into something where it's just like, "Well, let's just, let's just try something." Typically, we have some insight because of all these experiments that we've run that, hey, if we do this, I don't know, it's won here or it's worked here, it's driven this user engagement, if we, you know, sort of massage that and make it, you know, try it in this, um, you know, scenario or, like, a different screen, you know, we, we come in at least with a strong hypothesis that this will work. A lot of times, we do look and we're like, you know, a lot of the apps that we look at actually are games themselves. So it's like, all right. You're playing Royal Match or, you know, mono- there's a new Pokemon, uh, trading card game that I'm spending way too much time on. You know, you, you, you look at these games and see what they're doing, and it's really good, um, fodder for what we can do. But a lot of times, you're at least going in with a strong hypothesis based on what you've seen work elsewhere.

   8. SPSpeaker26:39

      Got it. So just to double down on that point, it's not, like, just random experiments. It's here's a hypothesis we're fairly confident, or has a chance to be true. Let's try it. It's not just like-

   9. SPSpeaker26:48

      Yeah.

   10. SPSpeaker26:48

       ... let's just try everything.

   11. SPSpeaker26:49

       And I think that, like, how strongly you feel about the hypothesis directly ties to how hard that experiment is. Like, with copy, for instance, we, we've actually set up really good infrastructure for copy testing. And I'm of the opinion that companies should run, as long as you have the user base to do it. Like, copy test constantly. Like, the amount of copy tests that we've had that is just, like, that have won, and, and you, I don't know, you just, you just try things and you figure out what wins, is, is definitely legion. And, and have shipped, like, massive wins from little copy changes.

   12. SPSpeaker27:18

       Is there an example of that, of just, like, the impact?

   13. SPSpeaker27:20

       Going back to that goal screen, um, (laughs) we used to say continue, our, like, standard CTA is continue. Um, and we changed that to commit to my goal, and it was, like, a massive win. Even just, you know, and again, it was like, ju- okay, users tapping on that. What are we asking them to do? Commit to the goal. What is that gonna lead them to do? Commit, not, you know, churn. Just that little copy change, that one time right there led to, to huge wins. And, and copy changes are so cheap. Like, it's just you translate a s- you know, for us, you know, we, we have a lot of, uh, you know, users all over the world and a lot of UI languages, so, but, like, just come up with a bunch of ideas, translate some strings. This is one where, you know, the, the feedback that you'll typically get from Luis a- so all of our changes at Duolingo go through product review that, you know, are reviewed by Luis. So Luis reviews every single change that, you know, we, we propose during every experiment that we run. Typically, with copy, he's just like, "I don't know. Test it." Like-

   14. SPSpeaker28:15

       (laughs)

   15. SPSpeaker28:15

       ... (laughs) there's, there's nothing better than to be told by Luis, "I don't think this is gonna win, but sure, if you want to." And a lot of times, you know, to his credit, he's right, and a lot of times, you know, our, our intuition was right. But it's just so cheap to do it. I think when the lift is smaller, it's great to have a hypothesis, but, you know, you don't need to beat it up too much.

6. 28:36 – 33:07

   Duolingo’s product review structure

   1. SPSpeaker28:36

      So on this thread, I didn't realize Luis reviews everything you're planning to change, and this may be the answer to the question I was gonna ask, which is one of the criticisms of running a product and company this way, of just experimenting constantly with all these micro improvements and changes is it can lead to something like a monstrosity of a product and experience that isn't consistent and cohesive and just, like, that often happens. Uh, is the solution to that having the founder basically review all the changes? Is there anything else y'all do to avoid it moving in a, becoming Farmville or whatever is a good example there?

   2. SPSpeaker29:06

      It, yeah, I, I, our, our product review structure where we've got our head of product design, one of the lead, um, you know, the, the product management leaders, and then Luis in PR, and because they see everything, it, you know, and they have a really high product bar, and so that helps. I think, over time, we just, as PMs, have to look at, okay, where is our feature headed? And so, you know, we do this with The Streak, at least on a quarterly basis, to look at, okay, well, what, what have we learned? You know, how has our streak developed, and how do we imagine this going in the future? I don't think... You know, it's, it's easy to do, you know, and end in some sort of awful local maxima if you're not constantly looking at your roadmap and think, and, you know, you don't have a clear strategy. You know, for me, it's like, if you have a clear strategy for where, where your feature is going, hopefully all of those A/B tests are not just done, you know, to get some cheap gain. They're done with a long-term goal in mind. I do think, though, and, and we do this every now and then with The Streak, eventually you just hit a local maxima, and you say... Like, you talked about launching neutral experiments, this is a great example where it's like, all right, cool. Now we need to throw a bunch of this stuff out. Based on all the learnings, can we reset this real estate? Can we reset this UI, reset this feature in such a way that is just as good as what we have now, but is way more plain or, or simple that we can, uh, again, start to layer on? Those are har- those are really hard experiments to, to get win o- you know, to win obviously, because they are so optimized, but they're really important to do. Otherwise, yeah, you just end up with a, a, a kitchen sink of a feature.

   3. SPSpeaker30:39

      One other, uh, tidbit I just wanna mention. Something that the adva- an advantage y'all have that other companies don't have is...... people want to learn, like they want to learn a language-

   4. SPSpeaker30:50

      Yeah.

   5. SPSpeaker30:50

      ... and so getting pushed to come back to an app for something that they want to do is not an advantage a lot of products have. So anything you want to add there of just like, this is why Duolingo might be a little different from what you're working on?

   6. SPSpeaker31:02

      I mean, that, that is definitely a benefit. If I had an app that w- I, uh, this is, this is actually why I think a lot of mobile games do streaks differently, because, you know, to say that you played a mobile game and th- as somebody who plays a lot of mobile games, uh, you know, that you've done it for 3,000 days in a row, like, I don't know, maybe that hits a little bit different than you've learned-

   7. SPSpeaker31:23

      (laughs)

   8. SPSpeaker31:23

      ... Spanish for 3,000 days in a row.

   9. SPSpeaker31:25

      Yeah.

   10. SPSpeaker31:25

       I think the comparison set is much larger though than a lot of companies give them credit for, you know, themselves credit for. And I think that there's, I mean there's a lot of ways that companies think about their... There are very few companies I imagine out there in the world saying, "Oh, we don't do some degree of good for our users." Uh, even if it's like a game, it's like, I don't know, you're like making your, giving somebody a, a, a, a moment away from the craziness of their lives. And so I do think though that is contingent on companies who are gonna figure out if a streak works for them, to figure out how can you frame the streak in such a way that a user does feel good about it? And it's easier for, you know, a Duolingo, but you know, I think there's creative ways to, to phrase this for users. You know, the other thing maybe just on that, that I'll say is, the streak works really well for Duolingo because with language learning, it's really hard to see day-to-day progress in becoming more fluent. Like become, and, and fluency is, is, is, is not even the right word. It's like becoming better at Spanish or whatever. It is a years long process for someone to get better at a language. I mean, Duolingo makes it easier, but you still gotta put in thousands of hours if you're gonna reach, you know, C1 or C2 fluency. And, and that is really hard to track on a day-to-day. And so the streak works really well for us because we not, might not be able to tell you, "Hey, you now know 0.01%, you know, more Spanish," but we can show you, "Hey, like, you've gotten your streak a little bit higher." And so I think this works particularly well when you're an app that is doing something that's gonna be sensed or felt over a longer term to help contextualize that progress in a way that makes more sense or at least feels more tangible to a user.

   11. SPSpeaker33:02

       Great. That was a great context, empowering to a lot of companies that aren't-

   12. SPSpeaker33:05

       Yeah.

   13. SPSpeaker33:05

       ... necessarily doing language learning.

7. 33:07 – 46:59

   Designing for clarity and adaptability

   1. SPSpeaker33:07

      Okay. So it took us on a long tangent away from lessons and experiments you ran along the journey of iterating on the streak. So a few things you've shared so far is just like it started being like, it started with this XP idea and then went to like a lesson. Then you iterated on ways, uh, to make it simpler, maybe harder. You added streak goals where you commit to like, "I'm gonna hit a certain goal of streak." Uh, what else, what else have you found that has worked, didn't work, lessons learned?

   2. SPSpeaker33:32

      You know, again, sticking with this one to seven day streak, you know, it, it is... The, the idea of a streak, particularly probably to this audience is like obvious, like, "Oh, it's a streak, it, you know, goes, it just counts how many days." We've realized over time that a lot of users do not understand how a streak works. And, and it can be as big as, you know, as small as, "Well, I don't understand how streak freezes work," or, "I don't..." Like my mom the other day was talking to me about it. She's like, "Oh, my, I like didn't use Duolingo and I come back and my, you know, streak's still there." So like there's like certain elements of the feature that, you know, we, uh, can do better at explaining. But even like what a streak is, it's, it's tracking how many days that I've used the app. Yeah, the more that we can make the feature easily comprehensible to users, the more retentive it is. And it, and, and we've run a number of experiments through this, you know, as simple, y- you talked about, you asked about early easy copy changes that we made. Actually, this is my first win, uh, experiment win when I joined Duolingo was, when you start a streak, we use, we have little copy at the bottom of the screen that just, I don't know, it's kind of like flavor copy, we use it to celebrate you or give you context. And I ran some tests that just like tried to, in eight words explain what a streak was. That was it. And it was a massive win because it really required, like it really dumbed down here is exactly how the streak worked and it really helped users, um, just understand what they needed to do. And I think this is something that's like you kind of constantly gotta remind yourself, particularly if you work in tech and you're building cool tech features, but your user base is not a bunch of tech workers, um, to like think about, "All right, who is my audience?" And for us it's not just like tech workers, it's not people in America, it's people all over the world of all ages, of all cultures. Um, and so making sure that your sh- your, your feature is, uh, even something as simple as the streak is understandable is critical.

   3. SPSpeaker35:27

      What was the actual copy? Do you remember?

   4. SPSpeaker35:29

      It was (laughs) it's still, I think it's still in the app. Uh, it's like, "Start a day to extend your streak, but miss a day and it resets." Something like that.

   5. SPSpeaker35:38

      That makes sense to me.

   6. SPSpeaker35:39

      Um-

   7. SPSpeaker35:39

      Very clear.

   8. SPSpeaker35:39

      And yeah, yeah.

   9. SPSpeaker35:41

      In, in eight words. I love that. Okay. And then when you say massive win, by the way, just to give people a reference point, what do you th- what does that look like? What is a massive win in this scale?

   10. SPSpeaker35:50

       Well, and it's, and it's funny, I mean this was, and this was four years ago, but I think it was like in the order of magnitude of over 10,000 DAUs for us. And actually maybe this a small bit of context. So Duolingo really cares about the metric CUR, um, current user retention rate. And actually our first ever Duolingo post, uh, with Lenny, uh, was the newsletter that our former head of product wrote, Jorge. Um-

   11. SPSpeaker36:11

       It's still the single most popular newsletter post of all time in my newsletter across 300 plus posts.

   12. SPSpeaker36:15

       And I would highly recommend that if you are interested in this, give it a read.

   13. SPSpeaker36:18

       Yeah.

   14. SPSpeaker36:18

       Um, you know, to, to summarize basically what we found is that if we wanted to drive DAUs and Duolingo cares, you know, our growth North Star is DAUs. The metric that is most, uh, uh, effective, you know, where a percentage change in that metric is, is most effective at driving DAUs is current user retention rate. And this is just users who are not new or resurrected, getting them to come back tomorrow. And so most of the work that our teams do, uh, our retention based teams do, is focused on CUR.Um, and so the retention team that I lead focused on CUR. It just so happens that Streak is the best feature at, at driving CUR. And so this was, this experiment was the biggest CUR win that we had had, it was like a top three CUR win anyway for us. Just this little copy, right? And that's why I say like, death copy a thousand different ways. Sometimes it's not the big beautiful feature, you know, that's gonna drive the huge gains, huge gains. Sometimes it's just something simple as a few words.

   15. SPSpeaker37:15

       I love this. Uh, okay. So when you... You said 10,000 DAUs. I think that references you guys measure im- incremental impact and absolute numbers of new daily users you're gonna drive with... Attributed to that experiment is what it sounds like.

   16. SPSpeaker37:28

       Yeah, and we, we, we do both. I mean, we'll also look at... Like a lot of times I'll look at, you know, for retention, day one versus day seven versus day 14. A lot of what I'm looking for is for us to have a better day 14... Excuse me, better day 14 impact than better day, day one impact because it means that users are retaining better over time. This is particularly for users that would see a feature multiple times. I just like absolute DAU numbers because it... As long as you're controlling for, you know, different biases like a recency bias, uh, or a novelty bias, it's a really easy way to just have an absolute comparison. You know, you start to look at percentage changes and then it's influenced by who your treatment, you know, how many users saw the experiment and... But at least, you know, uh, an absolute number is, is easier in my mind to start compare... Again, there are down... You know, there are pitfalls with it, but, um, we find that that's a pretty useful way.

   17. SPSpeaker38:20

       That, uh, lesson comes up a lot on this podcast and that approach to experiment.

   18. SPSpeaker38:25

       Yeah.

   19. SPSpeaker38:25

       So yeah, you're in good, you're in good company. Uh, quick tangent. If there's not an answer to this, no problem. Coming back to the idea of just like experimenting like crazy and not creating a product that nobody wants to use anymore long term. Is there an example of an experiment that was positive that you all decided, no, we don't actually think this is what we want in the product, that you ended up not shipping?

   20. SPSpeaker38:46

       You know, retention doesn't only work on the Streak, although, you know, you would, you would think... We do most of our work as the Streak. We've touched a lot of different surfaces over the years and there was one experiment that we launched that... You know, we talked about XP earlier. In the lesson, the only UI elements are a progress bar at the top and then how many hearts you have, right? So we keep it really simple. And this very much speaks to the design, you know, philosophy of Duolingo which is simpler UI is better. And we decided, hey, let's add XP in there. And so let's show your XP ticking up as you're going, you know, through a lesson. That's gonna make the user feel good. It's gonna give, you know... Show you what you've earned, you're gonna be less likely to quit. All these good reasons to do it. And then you finish the lesson and then we'll show you've collected all this XP and it, and it won. I mean, the hypothesis was a good one. Um, but we realized, and I remember having this conversation with Luis is like, "Cool, this is our most important screen in the app." It is our lesson, it is where users learn and the focus here is on learning, and now you've added this other thing up there to, to distract... You know, that could be distracting for users and I think the question... You know, we talked about roadmaps and strategy here. The question that he had for me and I didn't have a good answer for it at the time was like, "So what else are you gonna do with this?" Like, "What's your iteration ideas? Where is this going to go? Is this gonna make the, you know, lesson experience more gamified or..." And, and, and, and what we realized is that like... Honestly, it was kind of just a, you know, an easy engagement win idea, but we had touched our most, uh, you know, sacred space in the app to, to do that. And so that was a case where it's like, yeah, it was a nice win, but we'd added that UI element and, you know, at least at the time, it was less clear what we would do with it, and we realized that like long term it was just gonna get in the way. And we'd rather for simplicity's sake pause that. You know, shut it down and keep the lesson, you know, to be the... A little bit of a learning shan- sanctuary it was. Now, it's funny. Nowadays, I think we actually have enough XP-based mechanics and fun things that we can do that like, I think, actually a lot of our, um, y- you know, the, the beliefs about the in-lesson experience have changed such that something like that could work, but at the time, you know, didn't feel good to keep that around.

   21. SPSpeaker40:56

       That is an awesome example. Uh, hopefully we have time to talk about how the team operates. Where my mind goes is like, oh, but you have all these PMs and teams that want us to show impact in the performance reviews and all that stuff, and you're shipping s- you're not shipping something. They're like, "Oh, look. We did a win." So I want to chat about that later. But let's keep going on things you've learned and things that didn't work on the journey.

   22. SPSpeaker41:16

       The, the other thing that, that I'll call out with the, the, the streak i-... You know, it's like we have the, the image of the streak is this flame, right? And, you know, we have the streak flame and, and it's, it's very much core to our iconography. It's important to acknowledge that's a metaphor for a retention mechanic, like the idea of keeping a flame lit. And again, if you've... I think we've, we've established the flame as, you know, for a lot of users as sort of their understanding of the Streak, which is great, but there's a lot of people, you know, in different cultural context and different, you know, uh, uh, stages of life where the idea of like keeping a flame lit to show your commitment to something makes less sense. Um, we did some UXR in India many years ago and this was something that just like did not resonate at all, um, there, which was, which was a really interesting learning. And that's something, it's like, again, depending upon what your user base is, like, the more global UXR you can do to understand how users are actually understanding and experience your feature, the better, because you just, again, encounter insights like this. And so even our screen design, you know, we used to have a flame. It was just... It was mostly this flame that would like light up every day but again, it was like an indication of a metaphor for a mechanic. And when we redesigned it, we did this... Kurt, our, one of our animators, did this awesome odometer animation where it's like your number would tick every day. It like, kind of like looked good, but from a product perspective what was cool is we actually focused the design on the screen to, to show your number going up and then it would say, you know, like, "Seven day streak. Eight day streak." And I think that as you're thinking about designing around a streak, don't get too bought up, you know, or, or, or caught up into like, "We..."What is this, you know, like the beautiful story that you're trying to tell, at the expense of it being a really comprehensible feature? And so as you're thinking about product design, making that product design a clear distillation of this is what we're actually tracking. You know, form should follow function here, you know, was a, was a, was a learning for us. And you'll see that now in a lot of places where we're showing Streak, we're, we're really leading with the number, not necessarily the, the flame.

   23. SPSpeaker43:17

       That's all, that's a theme that I'm hearing again and again is clarity. Don't obsess with making it too th- like clever, and don't overthink it. Just like clarity has a big impact.

   24. SPSpeaker43:29

       Clarity also doesn't have to come at the expense of delight. And this is something where, you know, you hit a milestone and Duo gets the, you know, it becomes, we call him a Phoenix Duo and he becomes awesome and, you know, lights on fire. And I think there are things that you can do to still make the experience really exciting and delightful and celebratory, and, and I would, I would not lose that. But just don't do it at the expense ... And, and I think it's also about figuring out for what you, you know, you can get away with doing more of this for users who are deeper into their Streak experience than users who are starting where it's like, your goal for the One-Day Streak user is just to make sure do they understand how this feature works? I mean, even something again, just like another random experiment at the bottom of the Streak screen, we have a calendar. And over the years, it just looks more and more calendar-like, and that is simply because we find that the more we make it look like a calendar, days on top, you know, little circles, the check, like the more we make it look like a calendar, the more that people realize, "Hey, this is a day, a daily mechanic." And so think about the screen holistically, but every single thing that you're doing on the screen, how can you use it to communicate what is the point of this feature? How does it work?

   25. SPSpeaker44:37

       This episode is brought to you by Coda. I use Coda every day to coordinate my podcasting and newsletter workflows, from collecting questions for guests, to storing all my research, to managing my newsletter content calendar, Coda is my go-to app and has been for years. Coda combines the best of documents, spreadsheets, and apps to help me get more done. And Coda can help your team to stay aligned and ship faster by managing your planning cycle in just one location, set and measure OKRs with full visibility across teams and stakeholders, map dependencies, create progress visualizations, and identify risk areas. You can also access hundreds of pressure-tested templates for everything from roadmap strategy to final decision-making frameworks. See for yourself why companies like DoorDash, Figma, and Qualtrics run on Coda. Take advantage of this special limited time offer just for startups. Head over to coda.io/lenny and sign up to get six free months of the team plan. That's coda.io/lenny to sign up and get six months of the team plan. Coda.io/lenny. I imagine one of the biggest wins was just giving people flexibility, flexibility along the journey, like Streak freezes and all these things. Is that, is that a big vein of opportunity discovery?

   26. SPSpeaker45:52

       It, it is, it is cr- Actually, I'm gonna show you the-

   27. SPSpeaker45:56

       Oh.

   28. SPSpeaker45:56

       ... one of the most thoughtful gifts that anybody has ever given to me. This is our, uh, Duolingo serenity, our Streak serenity prayer. My, my co-lead Antonia, uh-

   29. SPSpeaker46:03

       It's like knitted, right? It's like a-

   30. SPSpeaker46:05

       ... for me. It's amazing.
8. 46:59 – 50:47

   Developing the Streak Freeze feature

   1. SPSpeaker46:59

      driver, you know, one of the earliest experiments we ran was going from used to only be able to have one Streak freeze, and then we let you have either two or three. So we tested two different arms. Um, (laughs) it was an, again, another huge DAU win. This actually is funny. It was something that, and this is again kind of a call- a callback to that growth model post from, from Jorge. It actually was really bad for because we were basically saying, "Hey, you can take a day off, you know, and that's okay." But it was really good for this is gonna be like Alphabet Soup IWAR, an active weekly active user retention, return rate. So basically users who had taken a day off, we were getting them to come back more at higher rates. And so it made up for our losses in But effectively what this meant is that, you know, why two Streak freezes work better than one was, I don't know, sometimes people just need a little bit more (laughs) flexibility than one day. But one of the, again, the really interesting insight of this experiment was that three Streak freezes was actually no better than two Streak freezes. And there were two competing things here, and I think this is important if you're gonna build a Streak, you know, to figure out what your flexibility mechanic is. We are getting more users to return after longer times away to an intact, you know, to an intact Streak. But if you start taking three days off from any habit, it's just gonna be less likely that you return even four days later. And so we had these competing things where users might, more users might be returning to a Streak, but a lot of users were also just not coming back. We were training them to, you know, take more time off. So that flexibility, what's the right amount of, I mean, we've, again, this is another area we've run hundreds of experiments on what is the right number of flexibility, what is the right amount of flexibility? And we, we are constantly surprised here. We, we don't, I, I still don't have the answer for every point in your Streak journey how much flexibility you need. One thing that I can say with certainty though is give more flexibility when a user is starting their Streak. Again, one of our biggest Streak freeze experiment when, I feel like I'm...... constantly saying this, "One of our biggest wins," but they all of we- were really, really big. One of our biggest streak freeze wins was when you start a new streak, we give you two streak freezes. And again, it's so funny to think back, it's like how are we not doing this to begin with? But at the time, the streak freeze was kind of an overly gamified mechanic, you had to buy them with gems, that's our in-app currency, you know, 'cause we wanted the whole idea of, you know, this, to feel like you, you know like it was really, you know, something you earned that, you know, there was a little bit of pain to getting that streak freeze. And so we tested though, ah, what if we just give users when they start off their streak two streak, uh, streak freezes? And holy smokes did that win. And it's sort of obvious now, you know, in retrospect, but if you have a one or a two or a three-day streak, it's really easy just to let it die and restart. You know, again, you need to get to seven days, uh, what we've seen in the data, for it to really lock in. And so giving users more flexibility so it's harder to lose their streak initially. And then conversely, and this is what we keep learning, eventually once people get on long streaks, you kind of don't want to give them as much flexibility. You know, because there's a lot of times where, yeah users don't... and I'm, I'm like this. I've got like a 400-day streak. Note that that is a lot less time than I've been at Duolingo. I have lost and restarted (laughs) streaks a lot of times in my time at Duolingo. Um, but you start getting on long streaks, and you really care about this feature. You really care about your streak. And most people, as long as you're not like backpacking through, I don't know, you know, the, the back country of, uh, Utah, you know, you'll, you'll be in a place where you can get service and so figuring out where's the u- you know, who is the user that actually could use Duolingo and not conditioning them to start taking days off that they didn't otherwise need to do is, um, is important to figure out sort of where that line is for, for your future.

   2. SPSpeaker50:46

      This is fascinating.

9. 50:47 – 54:08

   Balancing monetization and retention

   1. SPSpeaker50:47

      You can also buy a streak, right? Like with money. Is that... That's a feature, right?

   2. SPSpeaker50:51

      Yeah, you can buy... (laughs) And it's funny this is, this is also something that we-

   3. SPSpeaker50:53

      Like buy a-

   4. SPSpeaker50:54

      We wrestle with. Yeah, you can buy-

   5. SPSpeaker50:55

      ... streak fixer. Or, or freeze, sorry. Not a streak.

   6. SPSpeaker50:56

      Yeah. So you can, you can buy a streak freeze and the way it works is you can buy gems and then you can use those gems, um, to, to buy a streak. And, and this is something we wrestle with all... We're actively working on an experiment right now that's having a small hit to revenue, but it's a really nice win for retention. And I think it's actually worth thinking about from day one as you're building a streak, do you see this more as a monetization feature or do you see this more as a retention feature? What's the role of monetization in this? What's the role of retention? And I think for us it started out much more organically and so we have a lot of, like, monetization hooks that, again, as the retention PM, I would love to get rid of. Um, but again, it's sort of part of how the streak works right now, and so we always have this tension of, hey, if we start to make it harder to buy streak freezes, then fewer people buy them, you know, buy gems to buy them. And so there's this more convoluted, you know, series of impacts that happen. Um...

   7. SPSpeaker51:48

      Yeah. No, I love th- I love that, uh, people wanting to buy streak freezes like the ultimate sign of how much streaks matter. (laughs)

   8. SPSpeaker51:57

      Yeah. It's, it's streak- streak freeze is the other big one that we've, that we've recently demonetized or, or introduced a free option for is getting back a, um, a lost streak. So...

   9. SPSpeaker52:08

      Hm.

   10. SPSpeaker52:08

       ... when you start losing a streak, we add a feature, um, in the day, you know, back in the day called Streak Repair. We'd give you your streak back. You had to pay gems. But what we found out worked way better was a feature called Earn Back. And this is basically where you would have to do a certain number of lessons, as long as you came back within, you know, a, a window soon after losing your streak, do a few lessons, and we just give you your streak back. And it was such a retention winner and, you know, again, what we thought about was it feels like you've earned it so much more when you've done, like, you deserve to have your streak back. We haven't cheapened the streak, uh, because you've done something... And in this sense, this idea of cheapening the streak is something, like, from a philosophical, philosophy of the streak, from a philosophical level, we wrestle with all the time of, cool, we're giving out more streak freezes. At what point do we cross the line and users start to realize their streak means nothing? Um, now everything that we've seen, users are totally cool with using streak freezes and still thinking about their streak as this meaningful thing, but my co-lead Antonia who made that awesome cross stitch, uh, for me, she is sort of the keeper for us of the sanctity of the streak. And a lot of times as we... and I think this is e- this is really important to have as you're thinking about building your streak, you can almost always get engagement wins up to a certain point by just cheapening the streak. Making it easier to extend, letting users have more flexibility. But you kind of got to hold the line at some point. It's not clear where that line is, and once you... Like, you talk about one-way doors or two-way doors. There's a point where you go too far and it's a one-way door, and all of a sudden those users, those nine million users on one-year streaks don't care about their streak anymore. And that is, I don't know, again, retention PM perspective. That'd be an extinction level event for us. I don't, I don't want all of these users to stop caring about their streak. And so to have somebody who is invested in the, the sanctity of the streak and, you know, for us it's, uh, Antonia and, and Luis, he's very good about this, um, is really important just so you make sure you don't go too far.

   11. SPSpeaker54:06

       That's an awesome insight. Uh,

10. 54:08 – 58:15

    Notification strategies

    1. SPSpeaker54:08

       so to protect... and push notifications I think are another example of this in general for companies, like how much is too much 'cause everyone's just like, "Let's just send another push. It's fine. Just one more." Uh, and I... so your solution to that is a, a person is like the keeper and the gate, almost the gatekeeper plus the founder of how far is too far.

    2. SPSpeaker54:25

       That... It's, uh, it's good if you can, if you can have that. Um, I think push notifications are also easier 'cause, you know, there's a lot of things you can do around, all right, we'll set a budget cap for how many notifications we'll send. You know, you can, you can-

    3. SPSpeaker54:37

       It's like a create a policy.

    4. SPSpeaker54:38

       Yeah, policies. But I think with a lot of things it's, it's har- at least for the streak, it's harder to create policies for in the same way. A lot of it has to be done based on feel. And so you kind of just got to use your best judgment at times.

    5. SPSpeaker54:49

       Sweet. Okay. Any other maybe like a one or two more lessons from this journey of w- what streaks has become today?

    6. SPSpeaker54:55

       I mean, I can... You mentioned notifications.

    7. SPSpeaker54:58

       Mm-hmm.

    8. SPSpeaker54:58

       I- I've mentioned this a few times. One, it's funny. You- you- you tend to think of noti- like, exactly as you say. "Ah, you can just always send another notification. It's gonna be some win, and at some point, you know, it'll- it'll be a bad experience." But it's tough to see that. There's actually a notification that we... So we send two notifications relating to your s- core streak each day. The first is a practice reminder. We send it, this is actually an interesting insight, 23 and a half hours after you practiced the day before.

    9. SPSpeaker55:21

       Whoa.

    10. SPSpeaker55:21

        That is a long time.

    11. SPSpeaker55:22

        23 and a half, okay.

    12. SPSpeaker55:23

        So basically, if you practice at noon today, we'll send it to you at 11:30, uh, AM tomorrow. And we-

    13. SPSpeaker55:30

        And it's-

    14. SPSpeaker55:30

        ... have done-

    15. SPSpeaker55:31

        Because it's like, assuming they were free in that time the day before, maybe they'll be free the same time.

    16. SPSpeaker55:36

        And we actually moved... We used to let users set this practice reminder time and, you know, o- our thinking was, "Cool, you're gonna say, '7 PM, that's when I really want to extend my streak each day.'" And then you know what? I said this as somebody with two kids. Life gets in the way. Life always gets in the way, and when you think you're gonna practice, will change, your life will change, whatever. And what we realized is the best indicator of when you should practice was when did you practice the day before. We could almost certainly get more detailed. We have tried a bunch of ways to have much more complex logic, and what always wins is 23 and a half hours.

    17. SPSpeaker56:07

        That's so interesting.

    18. SPSpeaker56:08

        Um-

    19. SPSpeaker56:08

        Revealed behavior versus

    20. SPSpeaker56:09

        Mm-hmm.

    21. SPSpeaker56:09

        Yeah, exactly. Um, so- so we... Again, we send this practice reminder 23 and a half hours later. The other thing that we'll do though is we'll send a, what we call a streak saver, and this is at 10 o'clock at night, if you have not extended your streak, we'll send you a message saying, "Hey," you know, like, "It's- it's your last chance. This is, this is it if you don't extend your streak." And you would think that like, that's kinda spammy. Uh, that's- that's kind of annoying, to get a notification from an app at- at 10 PM. But what we've found is because people care about their streak, their streak is this good thing that they attach positive emotions to, that they don't really want to lose. That notification reminding them, "Hey, come back and..." Like, people see this, uh, uh, by and large as a positive notification and not a negative notification. Obviously, it serves our purpose as well of getting users to come back and not lose their streaks. But again, I think if you can think about your notification strategy related to what is the feature that it's tied to, how do users perceive that? You can almost certainly get a- uh, not get away with more, but you know, you can be thoughtful about notification load, um, and when to send notifications. And again, for us, this like late night message that's also highly impactful, super good, you know, is actually something that could be perceived as spammy. But a lot of our users really do... I, as somebody who it's often late at night (laughs) and I'm li- and I work here and I'm like, "Oh, forgot to do my D- you know, I was thinking about Duolingo all day, you know, here it is 11:15 and I still haven't done it." That message is, um, really powerful.

    22. SPSpeaker57:36

        Yeah, it has saved me many times. I-

    23. SPSpeaker57:38

        (laughs)

    24. SPSpeaker57:38

        ... totally know that message. And, uh, I love that it's like a late night message, uh, from an app. Very rarely do you actually are happy about that. And I love that this actually is a good example where like we-

    25. SPSpeaker57:50

        It's- it's-

    26. SPSpeaker57:50

        ... thank you.

    27. SPSpeaker57:50

        ... really, it's really funny all of the stories that you hear about people extending their streak. You know, if you look around a Duolingo party, uh, you know, where it's like 10:00, uh, 11:30, 11:45, all the Duolingo employees that are like doing their lesson at the last minute. Uh, you always see these like pictures of people in the club doing, or like at a concert doing Duolingo and yeah, 'cause it's like, otherwise that, you're gonna use a streak freezer, god forbid you will lose your streak.

    28. SPSpeaker58:14

        That's so funny.

11. 58:15 – 1:00:40

    The Perfect Streak feature

    1. SPSpeaker58:15

       Okay. Anything else? And if there's like more than one more, definitely share. But any other really interesting lessons or wrong turns or insights.

    2. SPSpeaker58:22

       You know, I talked about streak freezes and we've done a lot with streak freezes, but I think if you're gonna make flexibility a thing, it- it's probably also useful thinking about how do you celebrate perfection? Um, and so we have a feature that we have, it is the simplest thing in the world. It's called perfect streak. And it's just if you don't use a streak freeze for a few days, we make your streak look gold and we make your little progress bar on the calendar, um, just look a little bit nicer. There's no reward for doing it. You don't get anything other than this nice little indication. And it is awesome. It is, it is the, it is, it is- is a simple feature. It is ultra not complex, and it is really powerful. Not only for getting users to, you know, as- as a bit of a reward to be, "Hey, you know, get to seven days, you know, without using a streak freeze," and you know, your streak becomes perfect. But it's also a really nice indication of users who aren't using streak freezes. Here is the thing that if you, uh, you know, if you don't use a streak freeze, which again, candidly I would love for you never to use a streak freeze. If you don't use a streak freeze, your streak will stay, you know, perfect. It's funny. We- we actually just, you know, we're constantly, you know, responding to bug reports, uh, about the streak. You know, it- it is, I swear to God, we- we have that, we have the best infrastructure around this feature 'cause it is so important. Um, we had an employee who lost her like a four-month perfect streak. Uh, and you know, it was a big deal for her 'cause she, you know, and 'cause she like did her lesson and she was crossing international dateline. There was like a bunch of stuff going on that was like, it was just kind of weird in our backend. But like, people start to care about perfection as much as they do their streak. And, you know, for that person it was, it was- it was a big deal when they lost their perfect streak. And so, you know, this is just an example of look, if you're gonna, if you're gonna go after flexibility, um, which is good, finding a way to pull users back into perfection is a really important counterweight to have.

    3. SPSpeaker1:00:13

       What I'm imagining is you guys need like a Amazon style chatbot that just gives you the streak back. It's just like, "Okay, here you go." (laughs)

    4. SPSpeaker1:00:20

       (laughs) We have very much so we- we have... If people lose their streak, you know, there- there- there's ways to get in contact with us, but we've actually thought about that where it's like, okay, we should just like build a self-service feature and if your, if we think that your excuse is good enough, whatever, we'll just-

    5. SPSpeaker1:00:34

       Yeah, yeah.

    6. SPSpeaker1:00:34

       ... give it back to you 'cause again, it's for us-

    7. SPSpeaker1:00:36

       Don't even chip it back.

    8. SPSpeaker1:00:37

       I'm much rather you be on, you know, be on a streak than,

12. 1:00:40 – 1:04:47

    Enhancing the user experience

    1. SPSpeaker1:00:40

       you know, have lost it, particularly if it wasn't, you know.

    2. SPSpeaker1:00:42

       Right. But it also can't feel that easy. Uh, I love this. I also love this point about just the power of the animation and user experience having impact. That's really interesting. Is that something you find often just like making, like celebrating and making it feel really...... amazing without, like, copy or, you know, or like any features. Just, like, holy. You're awesome.

    3. SPSpeaker1:01:02

       This is another thing where it's, like, when users care about the feature using not only, uh, uh, animation, haptics-

    4. SPSpeaker1:01:10

       Mm-hmm.

    5. SPSpeaker1:01:10

       ... sound effects. Using... And it's funny, we don't have sound effects on the streak. I... This is probably something we'll look at in the not too distant future. But, like, haptics are, like, something we have done a lot of testing on.

    6. SPSpeaker1:01:18

       Like the phone vibrating in-

    7. SPSpeaker1:01:19

       Yeah. Exactly.

    8. SPSpeaker1:01:20

       ... in various ways.

    9. SPSpeaker1:01:20

       Your phone... You know, like, there being a really cool f- haptic pattern as you extend your streak. Um, all of this stuff wins. And it's cool because I think it wins... Th- there's a few reasons. One is it just makes you feel good, right? You know, you, you get some cool moment in your streak and, and, and we celebrate you and we celebrate you in this visual way and your phone's buzzing. It just, like, feels awesome. But the other thing it does is it, like, pa- causes you to pause on that screen and I think there's this desire as you think through a lot of... You know, as, as PMs think through, like, "Oh, how can I get users through this funnel as painlessly as possible?" You know, I talked about good friction earlier. There's a lot of times where I don't... I want you to stop. I want you to stop and, like, land on the screen. You gotta be careful not to do this for too many screens, right? But like, for the one big ones, sometimes I just want you to pause there and enjoy the moment. Um, 'cause if I can get you to enjoy the moment more, you're gonna care more about your streak and you're gonna be coming back tomorrow. And so, animations that are cool and that cause you to like, really soak it in. Haptics, you know, that feel good. All of that comes together to make you really focus on that moment. Um, all of that just gets users more connected to their streak. So, animation in the right times works well. Um, and it's something we've had win quite a lot.

    10. SPSpeaker1:02:29

        Who designs the haptics stuff? Is there, like, a haptic designer?

    11. SPSpeaker1:02:33

        For the longest time, it would be a product designer or ac- it initially started as, like, the engineer would be like... All right. You know, would cobble together haptics, um, based on what they felt good. Then it became a product design, um, role where they would kind of use their best judgment. We actually just recently acquired an animation studio, uh, Hobbs, in, in Detroit, and now they are the sort of keepers of, you know... They're... Do a lot of motion design work, haptics very close to that and so they do a lot of that. I do remember trying to hire for a while a haptics, like, contractor. They were, like, haptics design and it was the saddest hiring I've ever (laughs) done because it was just like... I don't know. Like, it was such a specific... Like I don't know. I, I just went through a lot of people who, uh... You know, it's, it's just a really tricky space of, like, kind of sound effects, kind of motion design, sort of technical.

    12. SPSpeaker1:03:22

        Yeah.

    13. SPSpeaker1:03:23

        Um, not-

    14. SPSpeaker1:03:24

        Such, such a unique role. (laughs)

    15. SPSpeaker1:03:25

        Very unique specific skillset.

    16. SPSpeaker1:03:27

        Right. And there's very few apps that really need this, this deeply, so you're almost n- creating this person.

    17. SPSpeaker1:03:32

        Yeah.

    18. SPSpeaker1:03:33

        That is f- fascinating. Uh, I don't want... I'm gonna... That's like a whole podcast on its own. By the way, I was gonna say, as you're talking about this, I love that, uh, it's a win to celebrate people that don't lose their streak. Like, you introduce this way to make it flexible and that's a big win, and then you g- go the opposite direction of if you don't use this feature, you also feel even better.

    19. SPSpeaker1:03:51

        Well, and it's funny, you... Like, you talked about the, the danger of feature bloat. We sort of talked about the danger of feature bloat. This is actually something I'm constantly thinking about with this. Like, we have the streak but then we also have the perfect streak and we can count how many- we count how many weeks you've had a perfect streak. All of a sudden, we have two streak numbers that are kind of competing with each other. It's funny, we actually don't introduce the concept of a perfect streak until after you've hit seven days, and some of this is just because the cognitive load of additional streak features. A lot of our, like, cooler streak features, you gotta get on a long enough streak. And not to say we haven't tested it 'cause we have 'cause we test everything, introducing these features earlier, but what we've found is that pretty universally, they lose when we introduce too many things, too many concepts to users too early in the experience. It's just hard for them to manage.

    20. SPSpeaker1:04:39

        Okay, sweet. I know that we can go down this track for, uh, hours and hours. There's endless learnings about all the things y'all have

13. 1:04:47 – 1:18:57

    Team operations and experimentation

    1. SPSpeaker1:04:47

       done along the journey. I wanna shift to talking about how your team operates. So, there's a lot of, uh, threads you touched on of just how a team can do this so well. Ship 600 experiments, as you said. Uh, continue to find opportunity. What are some maybe lessons or advice you'd have for folks that are like, "Oh, wow. I wanna work more like this." From your team's experience, how does your team operate that folks can learn from?

    2. SPSpeaker1:05:13

       Yeah. Maybe just a little bit of context. So, we're... Duolingo cares a lot about metri- so most of our teams are metric-based teams. So, we do the most work with streak, um, but, you know, our... The metric... What we really care about at the end of the day is KERR and DAUs because we see that DAUs hit KERR. And so, when you can be really laser focused on my goal each quarter is to make this metric go up, I think it's much easier to make sure that you're working in the highest ROI thing. I think when you think more about like, "Oh, I wanna make this feature better," I think it's easier to get lost in what better means and how you think about better. And so I th- do you think that, like, having a really strong degree of focus, you know, as, as a team on, you know, what is the metric that I'm caring about and how is that directing my efforts is useful.

    3. SPSpeaker1:05:59

       Versus feature-oriented. So basically, your teams are structured around a metric/a goal/outcome versus we own this feature or this process.

    4. SPSpeaker1:06:07

       So we... Retention owns streak, I guess. But that's only because we've seen streak drive KERR better than any feature. But we are not... I mean, we have this, you know, IAP, uh, hook with our streak freeze purchases. There are other teams that work on... You know, are... That, that can and have worked on the streak because it's not ours to say, "No, no, we do all the iterations here." We just know that it drives our metric better in the same way that, like, leaderboards. Um, you know, we have a team that focuses on how much time you spend. We want users to spend more time on Duolingo so they're learning more. Leaderboards is the best vector for doing it. So that team does a lot of leaderboards work but every now and then, I have an idea that I think will be highly retentive and I will go in and I will pitch to them and then we'll do some change to the leaderboard to make it more retentive. Um, and so... But I, but I do think having that clear metric of we're trying to drive KERR, not we're trying to just make this feature better helps at least.... make sure that, you know, give the team clear marching orders. And that focus, I think, is really good for prioritizing backlog.

    5. SPSpeaker1:07:07

       Cool. This is a really important point. This is the same way Airbnb worked when I worked there for a long time is it's, here's a, a goal that we want your team to be responsible for. You can work on any product you need to hit this goal. As you said, often, like various products are most c- connected to what you're doing, but what you're describing is like even though a team's kind of... Like I imagine you own it from a bug perspective and you kind of like are the shepherd of this part of the feature because it hits your goal, helps your goal most. But any other team can come in and be like, "Hey, Jackson, we need to work on some Streak stuff to help with learning." You're like, "Go for it." Does that... Just a tangent there. Uh, d- do they like work really closely with your team if they wanna do some work in the code? Is it like how does that work logistically?

    6. SPSpeaker1:07:48

       Yeah. I- if, if, if you're... Again, this is where I say there's soft ownership. We're not against teams doing things to the Streak, but if we're gonna do something given, you know, we probably have multiple quarters worth of a roadmap around the Streak... I say probably, we do, uh, multiple quarters of (laughs) roadmap, uh, for what we can do to the Streak, if other teams wanna come and mess with it, okay, we gotta just figure out how is that going to work with, you know, what, what our plans for the Streak were. How do we make sure a lot of times when teams are coming in thinking, "Hey, let's do this to the Streak," they're like in context that we might have. And so there's as much of like a much simpler version of what we're doing now, a bit of a knowledge sharing of saying, "All right. Well, this is what we think about the Streak. This is what we've seen work, hasn't worked. How does that influence some of the hypothesis that you have?" And so I think getting that really, um, making sure the juice is worth the squeeze.

    7. SPSpeaker1:08:32

       Good old-fashioned product management work right there.

    8. SPSpeaker1:08:35

       Yeah. (laughs)

    9. SPSpeaker1:08:35

       Uh, cool. What else is interesting about how y'all operate and how y'all work to achieve this sort of success?

    10. SPSpeaker1:08:41

        Again, my, my team lead runs, is Antonio, runs like the most eff- you know, th- uh, really process... If you're gonna run this many experience, you have to be really process-oriented and really thoughtful about which experiments am I gonna run when? How is that gonna set up the next one? We, uh, you know, uh, there's, there's heavy Jira automation. I think sometimes the Atlassian suite makes my eyes bleed, but like there's a lot of times where that degree of process helps the team unblock engineers and make them move really fast. And so making sure that you have really good process around how are you gonna run so many experiments, it's e- you know, it's, it's, it's worth investing in.

    11. SPSpeaker1:09:17

        Can you follow that thread actually? Just what do you... When you say that, what does that look like? What are some elements of that process to make this work efficiently?

    12. SPSpeaker1:09:25

        I- all the way down to, you know, really detailed roadmaps around, all right, we're running... This experiment is based on the results of this experiment or might, you know, uh, uh, uh, hook into an element of this feature. How do we make sure that we're lining up implementation on this so that as soon as this thing runs and we're ready to go, we can start rolling out the next one? You know, I hate features just sitting around and us not, again, continuing that thread. So it's not just thinking about what's our engineering bandwidth but also what's the design bandwidth to make sure that we have the next iteration of this feature ready to go. You know, we're planning months out as we think about these feature iterations, even small ones, um, you know, feature iterations because again, you just... You, you lose... When you lose cycles, you know, not pushing on a feature, it's just sort of lost opportunity. And so everything from manage, you know, being thoughtful about engineering roadmaps, to design roadmaps, to product roadmaps, um, all of that needs to come together in a system.

    13. SPSpeaker1:10:19

        So essentially mapping dependencies across function and you're saying in Jira you can do this.

    14. SPSpeaker1:10:25

        You can do a lot of it in Jira. There's a, (laughs) there is a non-zero amount of Google Docs that we have that sometimes does things-

    15. SPSpeaker1:10:32

        Yep.

    16. SPSpeaker1:10:33

        ... a little bit. I don't know, sometimes it just looks a little bit nicer-

    17. SPSpeaker1:10:35

        Yeah.

    18. SPSpeaker1:10:35

        ... it's a little more flexible. Um-

    19. SPSpeaker1:10:37

        Sweet.

    20. SPSpeaker1:10:37

        ... but Jira is our... It, it is where the mother load of process is.

    21. SPSpeaker1:10:42

        Great. Okay. What else?

    22. SPSpeaker1:10:43

        Like another thing that I'll, that I'll just say is like we really resist the urge to do the big V1. Um, and I think this is, you know, I, I shared the, the, the Streak goal example where a lot of times we'll... when we're exploring something, we will say, "Okay, well, like that's cool. How do we strip away a bunch of stuff and figure out what our core hypothesis is and then just ship that thing first as a V1?" Because it's, it's easy and- and I've found this time and time again, it's easy to add things to features that make them win. Like I've worked in retention and engagement long enough. I can like add... I know enough like things to pull and bells to add and whistles and, uh, you know, to make something win. But, you know, there's a lot of times where it's like cool they don't won because all the whistles you added, not because of what your core hypothesis was and a lot of times if you can just really simplify what the feature is, it's also much easier to ship. It's easier to design. You're not designing for a whole system, you're designing for, you know, something, something much simpler. Um, and so getting everybody to think that way ends up allow- you know, allows us to end up shipping faster, shipping simpler, you know, designing faster, getting faster approval, getting insight and then doing what, what I talked about with Streak goal, being able to run iteration after iteration after iteration, add these things iteratively. Um, and then, you know, you, you, you not only by doing this are you able to move faster, but you get confidence at each step of the way that hey, my series of hypotheses, you know, is actually borne out or if it's not, cool, then we're gonna drop that part of the feature and then just ship what actually matters.

    23. SPSpeaker1:12:18

        If I can try to summarize kind of, uh, a- the broad lesson so far that I'm hearing and maybe you, you would have heard this but I'm just thinking like if I were to try to design a company to operate the way y'all operate, you essentially map all the levers that drive the business so you have kind of this mapping of all the metrics that drive up the growth and re- and daily active users. You... CUR ended up being the biggest specific metric to move to drive growth long term. So there's like imagining a tree of all the opportunities you could work on, you found like this is what is most, uh, connected to our growth long term. You basically just start mining. Uh, I don't know if mining is the right metaphor, but just like looking for things that move that specific metric, you just like-... look and poke and explore. And then once you find one, you just go real deep on trying a lot of different... You, I, you come up with a hypothesis and a strategy of here's how we think we can do this and how we can move this, and then you just try a bunch of stuff. There's also this element of, uh, the, the Arrested Development quote, "There's always money in the banana stand," comes to mind, where it's just like, keep working on it. See if there's more, there's gonna be more opportunity at this... Yeah.

    24. SPSpeaker1:13:29

        When, when I joined Duolingo, um, the PM that I took over for Anton, who used to lead the retention team, I remember saying, "Dude. The streak, like, it just counts up. You guys have been testing on it for years. How much more work can we do on the streak?" And he was like, "Jackson, you child." He didn't say th- exactly this, but this is how I felt that like, "Jackson, you child. There is... So we're not even 30% of the way optimized." And four years later, I say that with like such conviction, we are so far away from what... I mean, we've made a ton of strides, but we are still so far away and every quarter where we ship a ton of, you know, wins and, you know, improvements to the streak, it just continues to prove to me that like there is so much more to be done. So, I, I think your framing of it is... And I would say, there's a lot of thought that goes into, you know, again, you know, I talk about the strength of the hypothesis that you have, you know, you have to have as you start to build that larger, you know, future strategy. I, I do think it's really important to not just do a bunch of random stuff, but do it with intent, you know, with a goal in mind. Otherwise, you do end up in these local, you know, uh, uh, local maximas. But yeah. I mean, there's still a bunch of stuff that we haven't tried that, you know, I think we have high confidence in, you know, working out and so we'll, we'll keep doing that.

    25. SPSpeaker1:14:44

        Are there any other, say, lasting lessons from this journey that if someone were to try to operate this way, build streaks into their product, anything you'd recommend?

    26. SPSpeaker1:14:55

        Yeah. I really do think it starts with... You know, uh, streaks are an engagement hack. Uh, you know, you can, you can make your app more retentive. I'm almost positive almost every app out there can make it more retentive. It wa- it is loss aversion. That is, you know, again, armchair psychologist Jackson. Like, it's just a human, a thing that works on humans. Um, but if it, if your, if your app is not something that users want to use every day or whatever, you know, cadence you want your app to be, uh, you know, to work on, it's gonna be you're only gonna get so much from that streak. And honestly, it's probably gonna distract you from what really should matter, which is making your app something that people want to use every day. And so if you start focusing on the streak but you haven't made that a enjoyable experiment, er, experience, you're just gonna waste a lot of time, honestly. And so I think making sure that you have your core loop of your app figured out, that, that it is giving value to users, it is something that they want to come back to every day, that really sets the stage for something to layer, uh, a streak on. So resist the temptation, if you haven't, you know, if you don't think you've reached that point, to go too hard down the, you know, the path of streak.

    27. SPSpeaker1:16:03

        That's a really good point. Just like, a streak is not gonna solve your problems if people don't actually care about the core value you're providing.

    28. SPSpeaker1:16:09

        No. And honestly, it'll probably cause more problems if, if what-

    29. SPSpeaker1:16:12

        Mm-hmm.

    30. SPSpeaker1:16:12

        ... you end up focusing on is how do I make this streak highly engaging but your app isn't, I mean, you're just, you're, you're, you're wasting time that could otherwise be, you know, better spent on solving more, more critical problems. So that's, that's one learning. You know, the other thing that I'll say is, we, we met with one of our board members, um, Bing, Bing Gordon a few weeks or, uh, uh, a few months ago rather, and he had this comment where he was just like, "The reason why users care about your streak so much is because you care about your streak so much." You being Duolingo. Like, "The reason why users care about our streak so much is 'cause Duolingo cares about the streak so much." We were like, "What do you mean?" Well, he's like, "Well, after every session, you see a big streak screen and it's animated cooler than almost any other screen in the app and then sometimes you see some other screens and there's all these other fe- like, you don't let a user forget it. You talk about them in messages." And, and so I think it's worth thinking about. Look, if you're gonna build a streak and then you're gonna second it off into the corner of your app, uh, you know, where users aren't gonna see it, like, they're probably not gonna care about it as much. And which might be fine, 'cause there might be other levers that you think are more important to pull on. But there's a reason why, you know, we focus as much on the streak, you know, as, as, as we do and that's because we want it to be top of mind for, for users. And that's not by accident then that users start to care about it. And so I think just as you're thinking about building the streak, making sure that you're giving it the visibility it deserves if you want it to have the kind of impact that Duolingo has, um, you know, is, is, it's- it's sort of an, uh, important hierarchy principle to, to think about as you design things.
14. 1:18:57 – 1:21:00

    Who can benefit from streaks

    1. SPSpeaker1:18:57

       Say someone's listening and they're like, "Should we do streak 'cause it's worth doing?" What's your take on just like the chances that a streak feature would be helpful to another consumer?

    2. SPSpeaker1:19:06

       (laughs) I'm, I am, uh, well known for saying in the company that I think every streak, every team, every app...... could, could benefit from a streak. Now, how you implement it is very different. And I think you gotta, like, f- what is your user's use case? Like, if they're gonna come use, I don't know, tax software. Okay, you know what? You know, now that I say this, tax software would be a hard one, but maybe it's all about, you know, you know, you need users to come back every day during the tax season, uh, or how many times ... I don't know. You know, now that I say this out loud, I don't know. (laughs)

    3. SPSpeaker1:19:35

       Times you upload your, uh, your bank forms.

    4. SPSpeaker1:19:37

       That is a hard, yeah, that is a hard use case. But I s- uh, the, the vast majority of, of, of, of companies, I think have a good idea of like, "All right, here is my ideal use case. I want users to come here three times a month." That, that would be ideal. You know, or four times a month. You can build the streak to work. I mean, Peloton has, has weekly streaks 'cause the idea of doing a Peloton, you know, uh, workout every single day is hard for a lot of ... It was hard for this user during COVID. You know, it was just, like, every now and then you get on the Peloton, that was great. But the idea of a weekly streak was something that I could keep up. And so, I think figure out what your usage pattern is, as a user, and then build your streak around it. But, you know, as long as you're not, uh, you know, the, like a really s- ... Uh, again, the, the tax example was probably a, a good counterfactual, but as long as you have some degree of frequency in your, in your use, um, I think almost anything can have a, can have a streak.

    5. SPSpeaker1:20:30

       So Duolingo, it's, again, a $14 billion company. This feature possibly the most contributing factor, other than the core, you know, product, to that level of success and market cap. And it's hard to imagine another just feature of a product that has had this much impact on, on growth and revenue and building this sort of business. So, I love that we spent this much time on it, a mother lode, (laughs) a mother lode of advice and insights. So thank you again for putting in Of course. For putting in the ...

    6. SPSpeaker1:20:59

       Very fun.

15. 1:21:00 – 1:28:31

    Lightning round

    1. SPSpeaker1:21:00

       With that, we've reached our very exciting lightning round. Are you ready? (lightning striking)

    2. SPSpeaker1:21:04

       I'm, I'm, I'm ready.

    3. SPSpeaker1:21:06

       First question, what are two or three books you've recommended most to other people?

    4. SPSpeaker1:21:10

       All right, I'll start with, uh, A Guide to Midwest Conversation. So I'm based in Kansas City, I'm a proud Midwesterner, and us Midwesterners talk in a certain way. I think, you know, you hear about Minnesota Nice, um, but we tend not to say what we mean, and it is a very funny primer into what Midwesterners actually mean when they say what they say. Um, so highly recommend reading that.

    5. SPSpeaker1:21:33

       It's great. I like that they, you give that to people, just like, "Here's what I might be telling you, which you may not read."

    6. SPSpeaker1:21:38

       Uh, my, my, my wife is German and I gave it to her so that she could (laughs) I could see German being the opposite of that. Okay. ... could better understand. Very different.

    7. SPSpeaker1:21:44

       I get that.

    8. SPSpeaker1:21:44

       Um, another book, uh, this is a good one, uh, Fate Is The Hunter. So this is a really cool book. It, it's a memoir of one of the early commercial airline pilots, and it is wild to hear the stories about what flying was back in the day. You know, I'm a former management consultant, I flew every week for, uh, almost six years, and I never once had to worry about, "Am I going to make it to the other end of this flight alive?" That was not the case back then. And so some of the stories about what it used to be like to, to be a pilot on some of these planes, um, before modern aviation technology is fascinating and makes you really appreciate what we have.

    9. SPSpeaker1:22:22

       It's, uh, it feels good to read a book like that being a software PM, or engineer, whatever, like how different that life is.

    10. SPSpeaker1:22:28

        Hardwa- (laughs) hardware is hard.

    11. SPSpeaker1:22:30

        Hardware, yeah. (laughs)

    12. SPSpeaker1:22:30

        Dick quick.

    13. SPSpeaker1:22:31

        Oh, man. It's not haptic design. Okay, next, uh, uh, unless there's any other books you're gonna share? No. Okay, great.

    14. SPSpeaker1:22:36

        Um-

    15. SPSpeaker1:22:36

        What's a favorite recent movie or TV show you've really enjoyed?

    16. SPSpeaker1:22:40

        Uh, so I have two kids, I watch a lot of Bluey. Um, it's really good, (laughs) I swear it's a, it brings me no shortage of joy. Um, but adult show that I, or, or show not meant for four year olds that I've watched, I just finished the latest season of Emily in Paris. Man, wonderful. Uh, I realize it's not the highest brow of television, but just, like, beautiful people and beautiful cities, solving problems that are not, you know, earth shattering, sometimes it is nice to just tune out. Also, I'm learning French on Duolingo. Uh, slight plug for the app, I can understand a lot of the French that is being spoken, and there is no better joy than having invested as much time as I have in French and actually being able to use it, um, so huge fan of Emily In Paris.

    17. SPSpeaker1:23:23

        That is so funny. What a fun Venn diagram-

    18. SPSpeaker1:23:25

        (laughs)

    19. SPSpeaker1:23:25

        ... of interests. Uh, my mother-in-law loves Emily in Paris. Uh, I saw someone tweeting about like, "What, what visa is she on? How is she still in Paris?" (laughs)

    20. SPSpeaker1:23:33

        Yeah, yeah, you're better to just not ask questions. (laughs)

    21. SPSpeaker1:23:35

        (laughs)

    22. SPSpeaker1:23:35

        There's a lot, there's a lot of questions for this show that are better left unanswered or unasked.

    23. SPSpeaker1:23:39

        Sure. Do you have a favorite product you've recently discovered that you really like, other than Duolingo?

    24. SPSpeaker1:23:44

        Last week I went to Home Depot and I bought a new ladder. And ladder innovations you don't think, you know, uh, uh, of often, but you can make one of the legs go a little bit further than the other leg. And as somebody like myself who has a house that is built on a slight slope, uh, every time I go up on my ladder, I take my life in my hands. But with this ladder, I'm always even. I cleaned my gutters twice last week just 'cause of how awesome this ladder, uh, has, has, how, how much this ladder has changed my life. So, ladder innovation, I don't think it gets talked enough about, and so I'm happy to give it the spotlight it deserves.

    25. SPSpeaker1:24:18

        I appreciate you doing that. It's the first ladder recommendation we've had on the podcast.

    26. SPSpeaker1:24:21

        (laughs)

    27. SPSpeaker1:24:21

        Two more questions. Do you have a favorite life motto that you really find useful in work or in life that you share with folks?

    28. SPSpeaker1:24:26

        This probably will not be much of a surprise based on how I've talked about our willingness to test things, but you miss 100% of the shots that you don't take.

    29. SPSpeaker1:24:34

        Hm.

    30. SPSpeaker1:24:34

        Um, I'm a big fan of just trying things even if your, uh, possibility of success is not 100, uh, 'cause you learn a lot among, uh, along the way, so ...

Episode duration: 1:28:31