A web content management system allows for the centralized creation, publishing, management and editing of online content. A CMS eliminates the need for time consuming, page-by-page creation of content. Typically, a CMS will allow for different user levels such as admin, editor, author, etc. that restrict users to certain functions within the system.
The most popular CMS is currently WordPress, which accounts for nearly 19% of the top 10 million website as of August 2013 according to W3Techs.