Before the OTF and ;0, I was at a ton of various websites and their forums. The first real one I stayed at for quite some time was Nintendorks. The forums were pretty busy, and the members were great, but due to too high traffic, the site closed down. They had an IRC channel, and it didn't die with the site and forums, so I hung out there a lot. After Nintendorks, some of the old members moved over to a site called Project Reality. There were not nearly the number of members, but it was still cool. (during this time the only online game I played was Command and Conquer: Red Alert)
On 4 July 2001, the world changed forever. My old neighboor came to our new house for the 4th, and he talked about TFC. I knew what TFC was and I'd had Half-Life since it was first released, but I never really figured out/tryed to download or patch the game and install TFC. He showed me how and downloaded it for me, and from that day on, I was hooked.
I played TFC everyday, and soon I heard about other HL mods. I think I found the CS Forums around August 2001. While posting there, there was a community called Forumthon. They had they're own server, which was a lot of fun until they came up with all these bullshit rules and the place went to hell. I saw Axe's swirly OTF signature with the info about ;0 irc, so I joined up. I didn't hang around a lot at first, but soon I became a regular.