Duolingo is an anticipated website, currently in development, that aims to crowdsource

Crowdsourcing

Crowdsourcing is the act of sourcing tasks traditionally performed by specific individuals to a group of people or community through an open call....

 text translation. One intended incentive for the users to take part is that they learn a language. Duolingo is a project of Carnegie Mellon Professor Luis von Ahn

Luis von Ahn

Luis von Ahn is an entrepreneur and an associate professor in the Computer Science Department at Carnegie Mellon University. He is known as one of the pioneers of the idea of crowdsourcing. He is the founder of the company reCAPTCHA, which was sold to Google in 2009...

and his research team. Duolingo launched in private beta on November 30, 2011.