acme has written a good piece about how cool IRC can be. I agree strongly enough that I'd like to add my pinch of salt here.
I used to hate IRC, or in fact pretty much anything relating to chatting. Most groups I'd seen were boring, or stupid, and often both. What's more, they were usually unfriendly and suboptimal in technical terms.
#axkit changed my mind about that. I joined it once a few months ago, probably because I was very bored and wanted to kill some time (or some similar reason, I don't remember). Since then, I've been having a window open onto it almost all the time.
The people there brilliant and incredibly nice, and I've learnt lots from simply hanging around and pinging ideas back and forth. Not only that, but stuff actually gets done. And not only on AxKit. Much, not to say most, of the recent developments that gave us SAX2 code took place there. New projects are being spawned on a regular basis, and lead to much interesting discussion. Sometimes, people even have solutions to problems you hadn't yet hoped of solving and were keeping at a safe distance down the line (eg Barrie's StateML).
In other words, IRC changed my mode of development. Instead of posting mails into oblivion and waiting for a kind soul to reply to see if there was something worth discussing in it, I just ping #axkit. Someone there will have a valuable opinion, and might even try to help the project directly. Some discussions can't be done with too much lag time.
I can only strongly encourage anyone with an interest in a topic covered by one of the friendly channels on rhizomatic to go check them out. It's often well worth it. Many thanks to those that make this possible.