EVERYTHING2.COM is a kind of proto-wiki, dating from 1999. Never as popular as wikipedia, it still has about 2 million pages, many of which show up nowhere else in the internet.
Archived by bbot. The torrent of the first two million nodes is here, (magnet:?xt=urn:btih:3da079e5932acdacfdf183ff6de1698b6f1a24b7&dn=Everything2+%280-2M%29&tr=http%3A%2F%2Fdenis.stalker.h3q.com%3A6969%2Fannounce) and a blog post on the tedious technical details is here.
Since E2 is an operational site, additional backups will be made as more content is added.