If you gaze deeply into the names of the people online, you may notice that if they are in the process of starting a new thread or leaving a new reply, their name will appear red (or black) on white background. I was thinking this might help you decide whether to stick around for another couple minutes, or not open a TNA PPV thread because you can see someone else is - although it didn't stop the two people in this world who care about Buff Bagwell from simultaneously starting threads, did it - well, at least it looks neat.
I may change the colours, or I may not. It's not something you're likely to see at any time but it DOES kinda stand out if you see it now.
If memory serves, the online users list is actually all the IDs that have shown activity in the past....five minutes? So you will linger on as a ghost for a bit after you log out, but you'll eventually disappear if you're not logged in, I promise.