"Moyer told AFP that Facebook or MySpace were not so much to blame as dumb users who stick things on their site which give out too much private information or add applications they don't need."

I think that comment hits the nail on the head, lets face it - the volume of sensitive information made available on these sites by dumb users is ridiculous 

"You should never underestimate the predictability of stupidity" - not sure who first said it, but you all know it is true!