TiddlyWiki - a non-linear personal web notebook
DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
wikidPad - wikidPad is an application for storing thoughts, ideas, todo lists, contacts, or anything else that user can think of to write down.
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Knowledge Workshop - Learning Management Solutions provides innovative and reliable software for the knowledge worker.
Confluence - Confluence is content collaboration software that changes how modern teams work