You enter, see a few ppl there.
You get bored of waiting for someone to say something and go browsing in another tab.
Someone comes and says something when you're not looking.
That person leaves.
You check back, and see you missed some chatting fun.
Moral of story: maybe a notification sound of some sort would be a good idea :P
I just died in there a minute ago.
I don't even have the chat open on Pidgin half of the time, lol.
IIRC most clients have a notification option.
Though if you're using the java applet, you're SOL