Apache JSPWiki - Apache JSPWiki is an open source Wiki engine, feature-rich and built around standard JEE components.
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
Linkpack - Save, read and share your links
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Pocket - When you find something you want to view later, put it in Pocket.