Luis von Ahn on Massive-Scale Online Collaboration
" After re-purposing CAPTCHA so each human-typed response helps digitize books, Luis von Ahn wondered how else to use small contributions by many on the Internet for greater good. In this talk, he shares how his ambitious new project, Duolingo, will help millions learn a new language while translating the Web quickly and accurately -- all for free. (Filmed at TEDxCMU.)
Luis von Ahn builds systems that combine humans and computers to solve large-scale problems that neither can solve alone."