Facebook recently changed its Terms of Service (TOS) in a way which explicitly gives them unlimited, forever rights to whatever content you post there. Three Groups have formed so far to fight this.
Read more about it here
Regardless of the fact that we all might as well accept that anything we put up on the Internet is there forever and can’t really be controlled, that does not give someone like Facebook the right to appropriate their user community’s intellectual and copyrighted property for their own possible future profit. That’s not sharing, it’s theft.