Anybody can post information about you.
Sure they can, Much in the same way the newspapers can run a story on you that you did not give consent for. The difference is that because facebook potentially store a lot of information on you and are constantly attempting to make it public. Whereas a newspaper article may stop at your name and possibly an embarrassing picture of you caught at mid pose. A facebook account may go as far as to divulge everything from your current location too you being 'tagged' in the aforementioned newspaper article; oh yeah and your back catalog of relationships, your parents and siblings, your dogs name, what side of the bed you sleep on etc...
And for what I ask you? I'm not about to write a Doctorate on what facebook is, but to me it's a load of people talking insignificant drivel (i can't believe you are still reading this :-) that most of the time struggle to make a coherent sentence. At the same time being bombarded with messages from people that want your money.
I also quit facebook today.