Facebook and other social media sites are dangerous ground and few of us use these tools safely enough. Even something that is said in jest or a quote from someone else can be used against you in court. Check out this article from the New Zealand Herald for what may be a startling reality check for you.
It is sad that the world needs tools like this but it is the reality. This is a great way for parents to stay better informed of what their kids are up to online and how others are interacting with them. It may be a bit expensive but what is your child's safety worth to you anyway?
Check out Reputation Defender's MyChild tool