One part of the OpenSolaris first anniversary (or birthday) last week was an IRC chat party.
I'm not entirely sure I'm fluent with IRC yet. I used to chat interactively 15-20 years ago, but haven't done much since. One problem is that I get interrupted or distracted quite a lot. This isn't much of a problem for email discussions, but it's rather easy to lose the thread of a chat conversation.
First couple of times I used the builtin mozilla client. Just tried the ChatZilla extension for Firefox, which is basically the mozilla client, and it works fine.