How Duolingo Reignited User Growth

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

Duolingo, which was also driven almost exclusively by word of mouth, optimized for free user growth: “By offering all of its learning content for free, Duolingo built a massive user base through word of mouth and no paid marketing. This also helped us build a growth revenue loop: Building a free and fun product → more users → more subscribers → mor... See more