Different users have access to different functions of the site. While anyone can do most things on the site, including reading and editing, administrators can access a few additional functions. * Deleting and undeleting pages and page histories. Administrators can also delete uploaded files, but cannot undelete them. * Locking (protecting) a page so it can not be edited or renamed by users without admin rights. * Blocking IP addresses or user names from editing; and very quick "rollback" of undesirable edits. * Editing the interface by changing system messages and skins.