That's why it's a stretch -- a serious stretch, IMO -- to believe that Foley was able to IM this young man 10 years ago. Not only that, but he (Foley) was able to -- somehow -- get his IM number. I will grant that it's possible -- probable? -- that the gay community adopted IM sooner than the rest of us did.
As a computer professional and geek I can tell you that 1999 - 2000 are the years that IM really caught on. AOL's proprietary IM protocol wasn't very popular, and the introduction (November 1996) of a free IM client by Mirabilis (ICQ) put AOL on its heels; which is why AOL bought Mirabilis in 1998 for nearly 300 million dollars. It took AOL another 2 years to integrate ICQ with their IM (AIM).
I can definitely recall using AOL IM's in late 95 or early 96 - definitely.