This Ted Talk was my first glance at the "idiot." Yes, Luis von Ahn is responsible for this system and I'm surprised that the audience didn't throw shoes at him at the beginning of his talk. But he turned out to be quite charming and funny. He has also redeemed himself somewhat by tweaking CAPTCHA so it is now something rather useful called RECAPTCHA - a means of digitizing books.
He has a new project which is even more interesting called Duolingo. This is nothing less than an attempt to translate content on the Web into multiple languages by helping people learn another language.