I've got a couple:
NaNoWriMo-This is my number one favorite
YahooAnswers(Books and Authors section)-my second most frequented tied with Fanpop.
Inkpop-which was my favorite and is now Figment so I don't enjoy it as much anymore.
Wattpad-But I'm hardly ever there because I really don't like it.
WritersCafe-Tried it out, wasn't impressed. I think I've forgotten my password anyways.
Accounts I have that don't have anything to do with writing include: