While facebook can be a privacy concern, it does not have to be since you control the info you place there, either when registering or posting. The trick, with everything online, is to be aware that anything you post online is both out of your control & permanent. If you always assume that what you post/upload will be read by your worst enemy & you avoid posting personally identifiable information (real name, location, contact info, etc), you can minimize the potential for privacy problems. Many government spy agencies operate on a need-to-know basis. That is, if the source requesting info does not absolutely, positively NEED to have it, then do not give it to them. I believe this is a good rule for all to follow.