MediaWiki

MediaWiki, according to its website, "is a free software open source wiki package written in PHP, originally for use on Wikipedia". It is now also used by several other Wikimedia Foundation projects and by many other wikis, including this one and all other Wiki.Wiki projects.

Resources

 * MediaWiki.org
 * Help:Editing pages
 * Manual:Installation guide
 * Manual:System administration
 * Manual:Upgrading
 * Manual:Extensions
 * Sysadmin hub
 * User hub
 * MediaWiki at Wikipedia