Jackson Shuttleworth (00:00:00): ... Duolingo is a $14 billion company, it's hitting all-time highs too, it just keeps going up, but I think it doubled in value in the past six months. Streaks is the most impactful feature. We have, right now, over 9 million users with a year plus streak. If you look at the numbers, I think it's been our biggest growth lever. What Duolingo really focuses on is, how do we help users build habits around language learning? Getting user come back the next day is the biggest problem to solve. Lenny Rachitsky (00:00:25): Let's get into the motherload of learnings from the journey of streaks, talk about the key lessons, insights, and also wrong turns along the way. Jackson Shuttleworth (00:00:30): I'd say test everything, we've 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 standard CTA is continue, and we changed that to commit to my goal, and it was a massive win. Lenny Rachitsky (00:00:48): There's so much human psychology that you all learn through all these experiments of just how to motivate people, what motivates, what demotivates. Jackson Shuttleworth (00:00:55): 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. Lenny Rachitsky (00:01:07): 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 spent 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 con...