It could be that mIRC is #1 because mIRC is #1, if that makes sense. Even if other clients were lightyears ahead of mIRC now, it takes a lot to make people switch. Especially if they chose mIRC through word of mouth. Things that come recommended always seem a bit better. I'm not suggesting that mIRC doesn't deserve the #1 spot, but rather even if it didn't it would take a while to make people switch to another client. It wouldn't happen overnight.
I disagree. Emoticons are mainly aesthetic, I'll give you that one, but they're also useful for showing the context you want your message to be taken in. Since there are lots of people on lots of different wavelengths on message boards and chat rooms, a joke may not always be taken as a joke, for example, but with a laughing or smiling icon it hints that you're not being serious. The same could be used to show anger, sadness, confusion, etc.
I was always under the impression that a large portion of IRC used English. When I say large, I mean more in the region of 70-80%, not a mere 60%. I could be wrong though.
Whereas you say it's fading out of existence, I think it's as popular as ever. I see tons of people using or discussing webcam every day. I guess it depends on the sort of communities you use, but I see them widely used in social networking ones (like myspace, etc).
I believe it's only used a little in IM applications because they're mainly used to talk to people you already know. I don't feel a pressing need to see my friend's face when I've seen it a bajillion times before. Whereas, on a profile site I use about 90% of the people in the chat rooms use their webcams. It's nice to hear/see the people you're talking to. It makes it feel like you know them more.
As far as voice is concerned, you only have to look at Skype's popularity to see it's not an uncommonly used feature.
