So, after a brief initial session with input from mouser, allen, m_s, jgpaiva and tsaint, it appears to be quite interesting. Not as good as IRC or your favorite IM client, but for folks who are not comfortable with those, it is easy to use and all it requires for private chat is a clear website (there are gabbly sessions going on at google and others...) and send your friend or relative a link. An interesting note: tsaint noticed that it got through a proxy that was blocking irc and icq type stuff. This may be a security concern in some circles, we'll see. Hmmm.. maybe it'll be a way for those in restricted countries (China, Iran, etc.) to make contact. I could also see this as a way of getting feedback from website beta testing, or web-based customer service implementation for small businesses, or... the possibilities aren't quite endless, but there is a lot of potential.
As far as features, it looks somewhat like a typical chat client without all the bells and whistles. It can be docked into a frame at the right side or bottom of your browser window, sports an RSS feed and of course, you can change your name and the chat window has a history, which is nice. That's pretty much it, check it out...