There are not many good examples of privacy violation up to now, but as more individuals participate and share info, the "problem" may rise.
You know, when "talking" with your friends, you actually want to do just that: talk with your friends. It is rather unsettling to know that most probably there are "eyes" that may watch over your info. These eyes are not FB's or Google's (they just want to sell things).
My examples may not be the best...but I do know that day by day, I feel that I lose hold of my data :(