I think you're on the right track. I really don't believe social networking sites are as great as people believe they are. I'm hoping its just a fad that will continue to die out.
Yeah, I honestly have mixed feelings (and a Twitter account, even though I abstain from MySpace and FB). I think that probably every kind of connection / communication technology is open to this kind of "emotional abuse" ...
I don't think that social networking will necessarily die, but I think it needs to develop and settle into some kind of form that protects people -- not just from predators, but also from drama. That may just mean that ultimately it settles down into something people use much less (without any new rules or structure or process) -- MySpace and Facebook automatically become a lot less dramatic if you're not on them five times a day. Twitter seems to me much less prone to putting people in a bad emotional place, also.