Interesting Social Networks? (Cool websites)

I’m interested in lots of social networks. I’m interested in hearing new ones. I have hundreds of accounts somewhere floating in the cloud. Facebook right now might be the best social network in the world. It has anything you can imagine. It’s just a bit ugly. What social network do you use regularly? I would love to hear it. Please share.

I don’t want to hear sites like FaceBook or Myspace.