I was active on RecTravelEurope on Usenet in 2001 when internet friend Robert Buxbaum told me that this guy, Steven Shaw, was starting a forum on food. "What's a forum?" So he described how special interest groups were going to take the place of cumbersome usenet. I joined in August, as member #80..
(Steve was the real pioneer. The progression was, AFAIR eGullet -> OA -> Mouthfuls and, separately, Chow.)