These sorts of sites are wide open to abuse and very little protection appears to be in place against those who would use them to abuse others, despite the obvious dangers. A the recent clearing of an adult who created a MySpace account impersonating a minor, in order to psychologically groom, attack and publicly humiliate a child of her aquaintance, demonstrates this. The known to be psychologically vulnerable child that this adult and her fellow 'conspiritors' (minors) groomed and attacked via MySpace, committed suicide as a result of the assault.

I deliberately use the term assault, rather than the more media pleasing 'cyber-bullying' ss I personally deem such deliberate virtual psychological attack, as a form of assault. In fact as an adult of 48 was involved (she also commented that her conversations with the 13 year old victim became "Sexual"), I'd be inclined to deem it a form of 'child abuse', albeit non-physical.

See here: MySpace 'Bully' Cleared.