None, because I don't have Facebook. I see it as a place for someone to gain easy information about you and then possibly use this information against you or your family in some way, shape or form. I also see it as a place for arguments to just flair up out of nowhere which is why I hate it most of all. 😛
I had over 800 "facebook friends" I honestly didn't talk to not even 1/4 of them, they just added me because they saw me around school/ campus or what not.
I ended up making a new one, but I only login once every few weeks and I talk to family members since I moved abroad. I'm certainly more conscious now about what goes up online.
I suppose a lot of it depends on the people that you come in contact with. For example, on Facebook, I enjoy the hell out of people because I refuse to reply with one-word or abbreviations. Oftentimes, I'll do around a paragraphs worth, and more recently, I have talked to a lot of people that will respond with their own block of text. 😛