Well, I'd say if you aren't a big fan of any kind of chat (especially IM) then you probably wouldn't care much for DC Chat.
The IRC channel is kind of like a real-time version of the Living Room section of the forums. Sometimes it's quiet for hours and hours and hours. Other times it's really busy with people talking about whatever. Sometimes people ask programming questions.
But it's a lot like the forums. Intelligent people in one location having (mostly) polite discussion on various topics.
Come on in, say hi, but don't be offended if nobody is around to say hi back. A lot of people just leave the client running all the time whether they're at the PC or not. Others just lurk and never say anything. You can come in and lurk and see what it's all about for yourself if you'd like. Though, usually weekends are a bit quieter in the channel because some weirdos have real lives and do things on the weekend.