I have got the impression that IRC is dying, you can notice that on the amount of girls that where around on mainstream channels around 1998-2000 and the amount now. Also in most channels I have visited since 98 mostly all have shrunk, and the iddling is far worse than its ever been before.
I think this is because of teen community pages that are very popular at least here in Sweden. Young chix dont want to chat on IRC because of all the guys that want to have cyber-sex with them. And when the chix are not around the guys wont come.
I dont think IRC will die off completely. But in the end only the pure computer geeks will be there. Just like it was in the beginning.