I know of a Police Dept that makes all applicants hand over their cell phones and log into ALL of their online accounts. Email, forums, etc. They don't give the people their passwords, but they have to let them access and look back at what they post, say, etc. When told this, some people walk out of the room. One guy and his wife were swingers and he had to sign in to his adult accounts, too. The PD was fine with it since it wasn't illegal. But then they found 3 or 4 more accounts that he concealed and the people he talked to a lot and hung out with were major bad news, criminal histories, etc, so he got kicked from the process, mainly for lying. Another guy had some incredibly racist videos of himself being an A** hole, he got kicked from the process. They also have a fake FB account that they make everyone friend and they monitor Facebook for their prospective employees and also criminals they are watching that the crims don't know about.
I have a FB account, but rarely use it; my brother and cousins post baby pics, family gathering pics, etc. Some of my friends post fishing stuff, etc. I am always aware that someone may be watching what I post, so I always try to keep that in mind! I don't have a problem with the social networking stuff, but I keep it to a respectable level. I don't have to be on FB all day long and comment on everything stupid thing people post.