Personally, I simply assume that anything I put out there is going to be fair game. So, I simply just guard what I put out there. I really don't have many secrets to keep anyhow....but I get the privacy concerns. Personally though, I enjoy keeping in touch with family and friends, and even long ago friends, classmates, and coworkers, etc. Not to mention, such networking is really the best way to stay employed these days.
We can fight the corporate oligarchy all we want, but its a losing proposition, and a war that has already been won, by them. At some point, you just have to decide if you're going to simply make the most of it, or wallow in misery against the system. I'm going to just try and be happy. Sometimes, I wish I was just another one of the ignorant sheep though, lol...but instead, I'll just try and be a happy wolf while donning my sheep outfit.