Hi Simon,
I am not sure if the forum has this capability or not, but I have noticed that other online communities have a small section that indicates "--- amount of users online now, and --- guests online now"
Also, some internet forums have the option to show if a user is currently logged in or not. This helps if someone wants to PM directly.
Just a thought.
Anyway, thanks again for this great forum! The work you do to keep it active is greatly appreciated!