Social networks and kids

I'm often approached by people who are very worried about allowing their kids to participate in online social networks. I think parents should be no more -- or less -- worried about this kind of environment then they are about any other environment their kids are involved in. Parents need to be present and involved until their kids are mature enough to be doing so by themselves. Even the mainstream media is having to report that the fears are more speculative, than grounded in real science.