Web based IM apps are fairly common.  There are several IRC apps and there was one designed by the ejabberd people (or at least somewhat related to the project) for Jabber.

Or at least that's what the service looks like.  I must say they are short on information.

That reminds me, I also started work on a web-based web browser at one point, called ``growser''.  Mostly for the irony aspect, I think, although at the time it was also a way of getting features like tabs into IE without any add-ons.  It also was a way of learning what could be done with DHTML these days.

http://www.masswerk.at/jsuix/ Got me beat.

That's bizarre.