Unlike HTML sites, CMS’s use scripting languages to sustain content on the server. These can be called as Portals as these too would require regular interaction with the server. PHP, Dot Net, ASP.net are common programming languages that are used to write CMS’s like WordPress, Joomla, Drupal, Vbulletin, MediaWiki, Plone, DNN, etcetera. The decision to use a particular type of CMS depends on the kind of usage that is referenced by the client
For example an enterprise requiring a content management system that needs to be hosting close to 9 Child sites and 1 Parent site on one server would need a Dot Net Nuke CMS (Irrespective of the number of DB’s). DNN CMS is secure as it breaks down content hosting into several folder levels and could use SharePoint capabilities too. Maintaining a DNN set of websites is a very tedious effort for the designer and developer
For a small requirement of a forum (discussion zone) content management system, PhPBB and WordPress are good options. For design based websites, Drupal and Joomla are efficient and highly flexible websites. For a Wiki (knowledge hub) kind of an interface, MediaWiki is thoroughly recommended.