How Streaks keep Duolingo learners committed to their language goals

Currency is for spending: Once customers are engaged with your system, giving them spendable currency is a powerful way to drive investment. This tactic is most effective if it’s layered onto other skill-building systems, instead of being used in isolation. Duolingo, for example, awards “lingots” for completing activities, which you can spend on cu

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Say you have 100,000 DAUs and a retention rate of 80%, and for every five users, one of them tells a friend each day to download your app (and they do it). You get 20k new users per day just from word of mouth. In this equation, Xn is the number of DAUs today and Xn+1 is the number of DAUs tomorrow:

X n+1 = (X n * 80%) + (X n * (1⁄5))

If you start w... See more