This is the kind of startup I believe and hope will survive when the current tech bubble bursts. They have a real technical solution to a real problem and are making their money by charging people for a service that is worthwhile enough to pay for. They're contributing to humanity in a meaningful way that's worthwhile.

All these social media sites that make their money off advertising or selling user data can all go bankrupt as far as I'm concerned. Their users are coming to their websites for the short-term dopamine rush brought by the novelty of social media interaction: these websites are not different in any meaningful way from drug dealers, and they're costing millions of people happiness and productivity. They sell themselves as communications platforms but in reality, they compromise on privacy and as a result some of the most important forms of communication are hampered by their influence. As developers I think we have an ethical imperative to work for organizations like Duolingo who are pushing humanity forward and not social media companies who are holding humanity back.