Though in terms of your average joe, no one seems to know about ICQ anymore. Those that do seem to remember it as something of the past (remember those days when we all chatted on ICQ?). Ironically though in Australia it was MSN that took over the market from ICQ. I guess because so many people had a hotmail account and the client came with their computer. Now if only people would switch so quickly to Jabber/XMPP as they did then, though I guess it would help if a popular phone manufacturer would do this by default.
I specifically mentioned Australia. Though I have observed trends for IM market share vary a lot more in different countries. So it's probably true that there is still some country where ICQ dominates. By the way, isn't AOL IM still the main game in the US?