It does seem a lot of people have a misunderstanding of how IRC works, and why it's so successful. With voice chat, secondlife, and other ways to have a conversation with someone, why is IRC still as popular as instant-messaging and even email? There are still MILLIONS of IRC users, millions of irc channels, and thousands and thousands of IRC servers.
IRC is multi-directional. As in, when you chat, it usually isn't one on one with just you and someone else. Though, it can certainly be that way, it's kinda against the theory. An Instant Messager client would be better for that. Instead, IRC allows you to talk to large groups at a time.
Just because people are in the user's list doesn't mean they should be chatting. Just like people in your Buddy List of your favorite Instant Messenger client aren't always chatting, and the people in your email Contact list aren't always emailing. A lot of the time, you gotta initiate the conversation by sending the email or double-clicking their name to open a chat box. In IRC, usually if you want to talk to someone specific you mention their name. What this will do is on that person's desktop, their IRC icon in the taskbar or such will start flashing. The IRC will somehow notify the user whenever it catches a Highlight. A Highlight is usually your name, or whatever keywords one chooses to be a highlight. For example, if you were in the IRC and said either "Selroth", "roth", "Draconity", "Draconomicon", and many other words, my IRC icon would start blinking on my laptop. And if I'm at my desk to notice the blinking, I'll open the IRC and perhaps engage in conversation if it interests me.
On a large server, that's always some kind of conversation going on in some of the channels. One can get completely involved in as many as they can to kill hours of time, just chatting. But, that gets boring after a while. People don't wanna chat if they don't find it relevant to them or interesting. So, it's also possible to set up highlights on a channel. Anything said in a channel can make that channel flash on the screen, or make the IRC icon flash - however the person using the client wants to set it up. If anyone says anything in #Draconity, my IRC icon will light up and maybe catch my attention if I'm not doing anything else. To be honest, I'll usually ignore it if it's someone I don't know who only says "Hello." That offers me nothing. If someone I recognized, I'll probably say hi back. Or, if they go beyond a basic Hello and start talking about something interesting, even if it's just how their day went, I'll probably engage in that conversation.
The Java chat client really doesn't do IRC justice. I can completely understand how many people expect those to be participating, because they don't know about the installed client most users have. They don't really understand how IRC works. So hopefully this cleared up some things. It's a bit too much to ask, as it's not easy easy as the single click on the "Chat" link above, but if you really wanna see why so many people love IRC even today, you gotta find a client like mIRC (google), download it, install it, and tell it to connect to irc.draconity.org on port 6680. Then, just leave it running. After 24 hours, you'll probably see a large conversation take place sometime in the day. If you say hello and talk a bit, then walk away, you may find that 2 hours later someone replied. Reply back, saying their name, and you're likely to have a conversation in real time!
Indeed, the key to IRC is idling. It's the same principle as being signed on / logged into AIM, IRC, MSN, Y!M, or whatever.