Just an idea, but maybe an on- / offline icon would be useful. That way you could see if a friend or somebody else is on- or offline. Something that could also be part of that category is a "armor-chat". Just a thought though.
We use to have one (The red button next your Profile name used to turn green). We also had a bit of text saying when you were last active. It was useful, but all of a sudden the site was extremely laggy. Pages could take forever to load (Or not at all), and it wasn't until the feature was removed that the problem was solved. So if it were to be added again, it must be differently.