A Content Management System (CMS) is a software application or set of applications plus related programs used to create and manage digital content. The beauty of a CMS is that it requires no software on the user's computer to upload or edit content. It is browser based and allows multiple users at a company or organization to update a site base. CMSs also allow for different user abilities, from high level (able to do anything on a site) to lower levels (write and edit an article without the ability to publish the article, which can only be accomplished by a user with higher abilities).  

A web content management system has two components: a content management application (CMA) and a content delivery application (CDA). The CMA is a graphical user interface (GUI) that allows the user to control the creation, modification and removal of content from a website without needing to know anything about HTML. The CDA component provides the back-end services that support management and delivery of the content once it has been created in the CMA.
 

Features can vary amongst the various CMS offerings, but the core functions are often considered to be format management, revision control, indexing, user management, search and retrieval and publishing.

 

With a CMS you can also deliver content to users according to predefined user access rights. Through a form on the public site, after a user logs in, the user will be presented with pages and content that are only available at that user's access level.