Drupal is a free and open source content management system (CMS) written in PHP and distributed under the GNU General Public License. It is used as a back-end system for over 1% of all websites worldwide ranging from personal blogs to corporate, political, and government sites. It is also used for knowledge management and business collaboration.
The standard release of Drupal, known as Drupal core, contains basic features common to CMSs. These include user account registration and maintenance, menu management, RSS-feeds, page layout customization, and system administration. The Drupal core installation can be used as a brochureware website, a single- or multi-user blog, an Internet forum, or a community website providing for user-generated content.