[dstik]

I've always been impressed by Duolingo's strategy - offering language education while distributing text translation.

Traditionally, language learning software like Rosetta Stone has been very expensive. Duolingo offers a free language learning service. As students improve/advance, Duolingo starts to use real sentences for teaching / translation. Because the other side of their business offers language translation services, the app can surface client's text to students and once enough students have attempted to translate it, their software compares and returns the best match to the client. [1]

Equally interesting, its founder previously started Captcha, which cleverly took the "prove you're a human" opportunity to have humans OCR books and street signs. Since the Google acquisition, I think ReCaptcha is now primarily used to improve Google Maps data.

I believe Duolingo has started exploring other revenue opportunities as this hasn't been as profitable as originally expected, but the idea is/was clever.

[1] https://unicornomy.com/how-does-duolingo-make-money-business...