Well, I used to spend a lot of time on
www.gurl.com when I was younger. I really like the message from website in general, but some of the indivudual forums have a lot of negative messages
from the posters regarding body immage and eating disorders... most of the forums are fantastic though IMO.
ETA: I don't want it to sound like this message board is negative... I really think it has a lot LESS negative aspects that the vast majority of teen message boards. However I really haven't looked at all that many... at least not in quite a few years!