Copydue - Top writers, on-demand for as low as $150/mo
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Mailbutler - Mailbutler adds lacking functionality to email clients and increases your productivity
TiddlyWiki - a non-linear personal web notebook
ArticleBunny - Get fast, professional articles at an affordable price
Confluence - Confluence is content collaboration software that changes how modern teams work