A good majority of us are on Facebook, MySpace, or some other online social network. For whatever reason, it has become very important to let everyone in cyberspace know what we've done, what we're doing, and what we're going to do, and we of course have the pictures to prove it. Sad to say, I'm guilty of it as well.
One of the biggest problems with the functionality of these networks is that it is extremely difficult to shut off areas of your profile to certain people without hindering the possibility of someone else finding you or viewing what you did today (which is the whole point of the network).
On many profiles there are definitely party pictures shared for your friends to see, that you do not want your employers or parents finding. There are also embarassing work picnic pictures your co-workers tag you in, that you may not want your friends to see.