Here's why I like it:
1) I used to use it for anonymous games, but I found that once I knew who the other guy was, it didn't serve a purpose after 1901 when initial moves were over and I gave up. Thrill of the chase, I suppose.
2) Most importantly, I use it, along with the time stamps in non-anon games to determine if a player has had the chance to look at my press. If I send someone press and see they're on, then I should be receiving a reply if they don't log off. There have been times that I've sent press to a guy who logs on, logs off and doesn't respond. Many hours later, I see them back on and they reply. In some situations, I've been able to deduce that they used the time to talk to my enemy and share press they've had with me to setup a stab.
3) On webdip, I use it to check which mod is on right now and can look into a game that needs to be paused, especially when I'm running a tournament. It's helpful when we run the School of War when a TA wants to coordinate with the player they're working with, etc.