I don't know how many people were using AIM in 1998, but prior to October 1997 nobody was.
According to the Wikipedia article on ICQ (http://en.wikipedia.org/wiki/Icq), ICQ was first released in November of 1996.
Somebody could have been using ICQ in 1997, but ICQ was the realm of geeks. AIM's following was more among the general population.
If AOL didn't come out till October 1997, thats only 3 months it was actually available in 1997. We should find out when this page left the Hill in 1997 and then count 2 months or so from then, and see if it fits the October 1997 timeline.
That guy is lying through his teeth. I love this site and the Internet!