I'm running DokuWiki now, although as a PHP application it is somewhat irritating to integrate with the rest of my server setup, especially with the nice URLs m

I'm running DokuWiki now, although as a PHP application it is somewhat irritating to integrate with the rest of my server setup, especially with the nice URLs mode requiring a bunch of rewrite rules. It is backed by plaintext files, has a decent permissions system, is decently lightweight, and has a fairly simple UI.