feel free to lurk in there and idle, it's the IRC way
It's true that not everyone feels comfortable using IRC. It's been around for a long long time now and after 20 years or so it's hardly changed. It's more of a "sign in and do your thing" type of app. Where you may leave your system on for days at a time, or at work, or while your watching TV or playing a game. That way you aren't constantly watching the screen waiting for someone to type something, you walk away and check back every once in a while whenever you feel like it. With many of us having several fellow members on MSN or AIM, sometimes it's harder to have a second app running because we may be too busy for it.
The biggest thing we noticed about the old weekly chat besides trying to find a good schedule, is that people tended to come in and out, drift off for a while when in the room or sit idle for long periods of time. That's exactly the kind of thing that IRC provides, albeit free of charge and not hosted on the site/server which frees up resources that we can use for other features.
Between using the forum for discussion and instant messaging, the IRC channel has yet to find it's niche. If anyone wants to schedule chats, feel free to do so. If you can pick an interesting topic to discuss or a debate, it may even spark the interest of more people.