Have you guys ever heard of the Internet Archive?
http://www.archive.org/index.php
It's actually pretty cool, you can go find websites the way they use to be. I've even managed to find a few on there that I use to visit before they closed down.
Anyway, this is Sosuave back on June 06, 2000.
http://web.archive.org/web/20000606231254/http://www.sosuave.com/
While I don't remember the exact date I found it, this is roughly what Sosuave was when I stumbled into it.
http://web.archive.org/web/20030217112919/http://sosuave.com/
The forums are actually archived on there too, so it's pretty funny to check them out. From the time I found it, most of the people aren't around anymore, some still are. In the first archive, I didn't recognize anybody at all. The topics being discussed haven't changed a bit though.
As for which came first, I'm not sure. I tried checking fastseduction but it's not archived, and I'm not aware of too many other community websites. Maybe someone else can check it out to see which ones were first.