What online social networking website would work for a language study group?

I already organize a foreign language study group on meetup.com, but I know that not everyone knows about meetup.

What event or group promotion websites can you recommend that I can use to find new members? Are there any sites that are specifically tailored to language study groups? (In the same way that goodreads has a section specially tailored for book clubs)

From web app MatthewMartin

• Google Wave is the most flexible social networking system I've yet seen. Indeed, it is so flexible that not even Google appears to know how to make best use of it yet. The Linguists of Google Wave public wave will give you a practical example, but do understand that this is a new realm to most of the participants. It is very hard to tell if this is an idea slightly ahead of its time or will be relegated to the dustbin of history.

  The only potential contender that I know of would be facebook, which - by its nature - prevents discussion of anything that takes more than two sentences to express. This answer would be a tl;dr for most facebook threads.

  From msw

• Well, there is Qlubb: http://www.qlubb.com/

  But that is even less popular than Meetup (at the moment).

  From Liggy