Confluence
A professional wiki, written in J2EE, with enterprise features such as PDF export, page refactorings, tight email integration, RSS feeds, a full remote API...
Proprietary alternative(s):
Jive Engage
Proprietary alternative(s):
Sharepoint 2010
Open Source alternative(s):
xWiki
Open Source alternative(s):
Drupal
Open Source alternative(s):
MindTouch Core
Saas alternative(s):
Google Sites
Go to:
Confluence's Web Site 