Alfresco Open Source Enterprise Content Management Software
Alfresco is an open source enterprise content management software. It features a content repository, which can be embedded in applications, and several products built on top of the repository: Document Management, Records Management, and Collaboration (Alfresco Share).
More information on Alfresco is available at Alfresco.com
Alfresco also maintains a wiki, forum and online documentation, which can often contain the answer to your problems. Several people regularly hang out at #alfresco in freenode IRC (Check out channel logs here). And, there is a Google Group called "Alfresco Technical Discussion".
The Alfresco tag here is best used for questions around configuring, extending, customising and building on top of Alfresco. For questions on installing and provisioning Alfresco, the Alfresco tag on ServerFault may be a better bet