Linux.com has a
review of DocuWiki. I've used/seen DocuWiki in the past, but for some reason or another I've never mentioned it here at
CMS Report. DocuWiki runs on a flat file system (no database required) and I've known people to choose it over others due to its easy to use ACL (access control list).
Created as a simple solution for managing documentation, DokuWiki has evolved into a powerful and flexible wiki suitable for most tasks involving collaborative editing. DokuWiki doesn't use a database back end (all pages are stored as plain text files), which makes it easy to install and maintain. Its access control list feature offers a user-friendly and flexible mechanism for restricting access to certain pages and namespaces. You can also extend DokuWiki's default functionality using plugins, and there are hundreds of plugins to choose from.