What Drupal is
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 2% of all websites worldwide ranging from personal blogs to corporate, political, and government sites including whitehouse.gov and data.gov.uk. It is also used for knowledge management and business collaboration.
Tanagra has been specializing with Drupal since 2008, and has selected Drupal as the leading technology platform for integrated websites.