A content management system is software that keeps track of every piece of content on your website. It allows for publishing, editing, modifying, and maintaining content from a central interface. CMSs can be used alone, or in conjunction (integrated) with other applications. They can be set up directly on a network, the Internet, or even to run "locally" on your own computer.
The most widespread use of CMS today involves the quick creation of powerful websites that do not require a high level of programming knowledge to set up, customize, and maintain.
Some common CMSs are: Drupal, Joomla, and Wordpress.