When you enter the Chat room, you can see how many people are online or idle. However, you cannot enter chat unless you are logged in.
Would it be possible to have a count of on-line users that is visible from outside of chat, or if you aren't logged in?
We could get a count of posts since you last visited chat, as well.
This is just a suggestion; it might not even be feasible.
I thought this would have been suggested by now, but I couldn't find it.