I only defriended one person who did not seem to understand boundaries and used information gained from Facebook to almost stalk my daughter. The person was very inappropriate when my niece passed away by discussing the cause with people we work with. I get to know people better before inviting them into my life. I am normally an open and caring person who gives everyone the benefit of the doubt. But because of personal nature of posts from family and friends I have found you have to be more careful about who you allow access. Yes, I know there are all kinds of ways to get into FB, it is that secure.