they are relatively easy to write as a java applet and there are likely already several free ones out there to use.
off the top of my hand, the excuses to argue in favor of it would mainly be that people could chat realtime (duh), you could put it in a frames system similar to elitemail so that you could rotate the banner ads above it - hell, below it too... all around it. it might draw or retain a few more people. you can log the discussions and then generate a web page from that, allow searches against it, and of course let it be indexed by search engines and then more people will find your site.
the reasons to argue against it - I'm not sure if it is the case with the 1.3 release of the jdk, but with the older ones, the java applets that got a lot of traffic tended to bring down the server over time and require a reboot, and then after some time it would do it again... over and over again. this is annoying. and it is one more thing to maintain and more work.
I'm perfectly happy with the current set up - well, pretty happy.
It would be kinda neat..but I would go with the idea of the avatars.... at least 500 posts... and also possibly giving "boot" powers to some of the vets on the board (boot meanig boot them outta the chat room) Did I just volunteer for that??
This is a brilliant idea which has been thrown around this board for a long time now.
The only other BB'ing chat room I use is www.getbig.com but it run's very slow, and it's full of natural prick's banging on about the danger's of steroids. Come on George, where's our chat room.
I threw this idea up about a month ago... no one really saw the need for a real time chat forum with all these discussion boards ... its harder to say something witty when you only have a couple seconds as opposed to a half hour to ponder your response.