Drupal /ˈdruːpəl/ is a free and open-source content management framework written in PHP and distributed under the GNU General Public License. It is used as a back-end framework for at least 2.1% of all websites worldwide ..
The standard release of Drupal, known as Drupal core, contains basic features common to content management systems. 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 simple website, a single- or multi-user blog, an Internet forum, or a community website providing for user-generated content.
As of August 2013, there are more than 22,900 free community-contributed addons, known as contributed modules, available to alter and extend Drupal's core capabilities and add new features or customize Drupal's behavior and appearance. Also Drupal has 30,000 Developers (As of 11 November 2013).
From July 2007 to June 2008, Drupal was downloaded from the Drupal.org website more than 1.4 million times, an increase of approximately 125% from the previous year.
As of August 2013, more than 910,500 sites are using Drupal.