Majority of people who are heavy users of Face Book, are just bragging about their lives, what they have etc. That's why Facebook website called that.
Nah, it's to make huge amounts of money with virtually no real world constraints (tax, open API, privacy & data protection or lack of it....) What really burns my Tos is that even if you choose not to participate, they will get you via buddies sharing contact lists and the like.
I think that Facebook's real purpose is to keep its owners rich. I suspect that all the surveillance and data collection are just side-effects...