Drupal is an open source web content management platform powering millions of websites and applications. It’s built, used, and supported by an active and diverse community of 630,000+ users and developers around the world. The software is distributed under the terms of the GNU General Public License (or "GPL"), which means anyone is free to download it and share it with others.
Drupal is used by some of the biggest sites on the Web, like The Economist, Examiner.com, Fast Company magazine, World Wildlife Fund, and The White House.