Shanghai-based italki is “applying Web 2.0 concepts, such as social networking, user-generated content, and crowdsourcing, to language learning.” Founded by American and Chinese entrepreneurs, italki has 210,000+ users from 100+ countries speaking 90+ languages. They have recently launched a new version, where users can “now collaborate on creating free language learning textbooks”, according to Kevin Chen of italki.

On italki, speakers of different languages can exchange questions/answers regarding the languages they are learning. For example, as shown on the screenshot below, those who are learning Korean language can post questions, for which Korean speakers (like myself) might provide some help.