In another (what can only be termed d!ck) move by Facebook, your already useless and good for nothing private life, is that much lesser private. I did hear about logging out from facebook while browsing, but this supersedes everything that they've ever done. Becoming a necessary evil in my opinion, Facebook is at the cornerstone of every publicity campaign, every awareness ad, and every child that'll get a dollar for every like or share he/she gets. The importance of one's privacy is not something one takes too seriously in their early years, but when embarrassing pictures start surfacing a few years down the line, eyebrows are raised. Better to be safe now, than sorry later. All major companies, HRDs are using Facebook as an effective tool to understand and learn more about their employees, if not keeping track of their movements thru their updates and status messages. What they like, dislike, what their opinions are, everything is being monitored. Don't post something stupid now, and regret it a few years later when your company or for that matter your girlfriend digs it up and starts questioning. Knowledge is information, and this information is money. Sadly it's at the cost of our privacy, and with every intrusion it gets smaller and smaller.
Use Facebook from devices that are not connected to internet or any other form of network. Better be Safe than Sorry.
I donno be invisible, not provide them with any information like me, be obscure, misdirect, make yourself unavailable.