talk.origins
The Usenet group for the evolution-versus-creationism debate, which spawned one of the first large fact archives on the net.
It started life as net.origins and landed in the talk.* hierarchy at the Great Renaming — the designated home for arguments that would never end. Biologists, geologists, physicists and believers of every stripe met in a debate that ran daily for decades. The same objections came round every month, and the people answering them grew tired of writing the same replies.
The fix was a FAQ system that grew into the TalkOrigins Archive, a website from the mid-90s with long-form articles and an index of creationist claims paired with rebuttals. The group also coined PRATT — "point refuted a thousand times" — for arguments that no longer deserved a post of their own. It's hard to find a better example of Usenet turning an endless quarrel into documentation.