New QuickChat extension lets you chat with other website visitors
"This is a great new Firefox extension that will let you chat directly within Firefox with other people who are visiting the same website you are...Great use of an AJAX extension to let you chat with people who like the same sites you do." They've gotten this up and running, after the server being down for a bit. It's basically a Firefox extension based on the cgi:irc chat client. The cool thing is, it creates channels based on what website you're browsing, so you can instantly talk to other folks who are there. Very slick.
Right now it's pretty basic, but they'll be adding new features soon, according to the guys who built it.