Yes, people don't realize just how much information they're sharing about themselves online. Whether it be to Facebook and its advertisers, your boss and his standards, your mother and her rules, or your significant other and their suspicions.
No, people who think that Facebook is ruining their lives are just irresponsible and stupid. It's not Facebook's fault you cheated, fool or you went home past curfew!
I don't really know. But Facebook's popularity should point to something.