I think it's wrong that companies spy on people through social networks, but if people are stupid enough to post certain things and disregard privacy settings, then they're probably not smart enough to keep their jobs. If it's something they can't say to their boss's face, then they probably shouldn't say it and risk their position... Unless they're positive they can get a better position in another company that pays more.
Do you know how many people have gotten in trouble at work because they posted pictures of themselves totally sloshed at a weekend party?
It's fucking dumb shit like that I have a problem with. Some people get in trouble for merely having a bottle of beer in their hand because the assumption is that this person is some fucking drunk when that could have very well been their first, and only, beer the entire night, but, people see a picture and form a conclusion.
Your personal life if your personal life. I get that venting on a social network doesn't make it as private/personal of a life anymore, but, still, you're away from work and if donkeycock at work is being a faggot, people should be able to post about it. Maybe if he sees it, he'll tuck his imaginary 10 inch dick in his pants and realize he is only a 2.