Content Management System - includes solutions/tools for publishing, format management, revision control, indexing, search and retrieval.  When selecting a CMS for your website, be sure to factor in SEO so that your CMS will be able to handle items such as populating unique title tags, meta data, page copy, text links, SEO friendly URL structure, redirects and the like.

Some of the business benefits that can be obtained by implementing a CMS, include:

• streamlined authoring/publishing process
• quicker turnaround time for implementation of new pages and optimization changes
• greater consistency
• improved site navigation 
• scalability
• reduced site maintenance costs

Examples of content management systems include:

Vignette - http://www.vignette.com/Products/
Documentum (EMC) - http://www.emc.com/products/family/documentum-family.htm
Interwoven - http://www.interwoven.com/
Joomla - http://www.joomla.org/
Tridion - http://www.tridion.com/products/
Typo 3 - http://typo3.org/about/about-typo3/
 

CMS Resources

CMS Matrix - http://www.cmsmatrix.org/
CMS Watch - http://www.cmswatch.com/