WSJ video, "The Economics of Duolingo"

Video talks about:

• How they keep all lessons free

• How they get revenue from only 8% of users paying

• How they use experiments

• 2:30 - talks about how they use experimentations

  • A/B for notifications

  • Sending a "this is our last notification we will send you" got people to come back

  • The messages you get aren't the ones everyone else get

    • to do this, Duo made an algo called the "Bandit" algorithm, which is a reference to a slot machine in a casino.

    • They try each notification at different times, see which one is more effective

    • They run more than 10,000 A/B tests

    • CEO, "without running those A/B tests, we would not be successful as a company"