Among the recent wave of Facebook changes that seem to have everyone up in arms (although I think people are getting used to it now). Facebook changed something and did it right for a change. They added a bit more functionality to their chat feature.
Facebook chat was basically an all-or-nothing thing. When you were on, you were on and all your friends knew it. But what if you didn’t want to appear online to some of your friends? What if, hypothetically, you didn’t want your “work friends” to know you were on…well now you can.