I've been following what are now called social networks right from the start. As an English as a foreign language teacher, I soon realized that they could be one way of solving one of the essential problems of learning a foreign language, namely communicating with real live speakers (and writers) who use the language as it is used daily, not as textbooks and professional teachers water it down to help learners learn it, or even as newspapers or news broadcasts transform it to suit their needs.
I soon 'required' my students to join Tagworld
, not because it was the best or the most popular, but simply because it suited my requirements at the time. Here's the address:
Every student had to make ten posts, 5 "personal", ie on any subject which interested them; 5 'professional', ie in their major.
The real point of the whole exercise, of course, was to get them to make contacts with real English speakers. It worked for some; others hated it; others just did what was asked of them.
One great thing about it is that it actually helped some of them make progress and contacts. I consider that as a "mission accomplished."