My editor just turned me onto Figment.com, a cool site for teen writers and adult writers of teen lit. You can post stories, share work, comment, design covers ...
I'm posting it because I get emails from fretful parents of wildly imaginative, feverishly writerly kid stock, wondering how to encourage said kid. Mostly, you should get out of their way and give them the space to write what they want. But there are also cool camps -- like Shared Worlds, for example. I know that as a teen I kept quiet about wanting to be a writer, as it sounded like such an uppity thing to want to be. I didn't know other teens who were squirreling away words. Maybe they just weren't talking about it either. Figment.com would have been interesting to me, I think, to get some feel for another kind of community.
For anyone looking for writing retreats, conferences, workshops, a good listing can be found here.