A friend of mine is working on something called Wallop. It got featured in Wired recently and he tells me that they're gonna be opening invitations soon. I've been a member for over a year now, but since I can't invite anyone in, I haven't been using it much.
Actually, my friend says that the idea is to have small networks for friends actively sharing their blogs, music, pictures, etc. in a dynamic way that the other social networking sites have not quite put together yet (though flickr is pretty cool.) I'm psyched about this and you should be too. I guess they'll be allowing some invites sometime this fall, so if you want in -- let me know!