Hmmm... this prompted me to go and do a search in the forums I remember reading in my early days to figure out where my first post was.
I figured it had to be in the AA forum where I have been the most active - and I found one there from mid-August 2001. A further search found one a couple of weeks earlier in the Hilton forum from early-August.
Then I found post #1 from July 2001 - ironically enough responding to come to an event hosted by a couple of (then) strangers who I have come to know much better (and one of whom is now a dear friend).
Funny thing was, I participated in FT Chat before I ever posted... thus my registration goes back to March 2001. I think I have to have been a lurker for two years prior to that, too, as I first found the community in 1999.