Looks like AOL accidentally banned 10.000 users last week.
I find it doesn’t really matter which IM protocol you use, as long as the software you use supports them all (plugins). I use Miranda.
AIM is the one I have the least friends on, most people are on ICQ, a few on MSN and some on jabber or yahoo. The whole thing is completely transparent. And if AOL shuts down AIM tomorrow because they don’t make enough money on it, all that means is my friends on AIM need to find another client, not me =)