With Google trying to break into the mainstream social networking market with Google Plus, Facebook has been busy with a number of changes of their own. One of the most controversal is a new feature in the top right side of the screen which allows you to eavesdrop on your friends and see things they are sharing with others on Facebook that have nothing to do with you. You could always click on a person and look at their wall posts. Now Facebook has brought that to you without you having to consciously going to look for it.
Social media is inherently open. If you or your kids use Facebook, I would suggest you click on Home and the both Account Settings and Privacy Settings. By going through each of these settings you can control who can see what about you (i.e. the world vs. friends vs. friends of friends who you may not know). It also controls what information of yours your friends Facebook applications can collect and share about you. Personally whenever there is a choice, I limit the setting to friends or friends only. From time to time Facebook also changes and adds options as Facebook adds functionality. Therefore, it is always a good idea to periodically review your account and privacy settings to make sure that some new default setting for a new feature is not providing more information about you than you would like.