Crowdsourcing language translations

Crowdsourcing is the practice of asking the public to help perform a given task. These days, the internet is often used for the asking and for the performing. The most recent example is Twitter crowdsourcing the translation for its international editions, via a “Translation Center” website. Here is how it works:
Volunteers sign in to Twitter, then go to Twitter’s Translation Center to select a language they are fluent in. They can suggest translations for different phrases from the Twitter home page,  Welcome Email, Terms of Service, etc. or vote on translations that others have already suggested. Twitter chooses the best translations for each phrase based on recommendations from the community. [Source: The Language Blog]
Flattr has done the same thing for its website.