Drupal

Drupal is a free and open source content management system written in PHP that competes primarily with Joomla and Plone. The standard release of Drupal, known as Drupal core, contains basic features common to content management systems. These include a dashboard with a menu management system, RSS feeds, page layout customization and themes to aid this, and system administration tools. Drupal offers access statistics, more advanced search features, caching and feature throttling (to improve performance if needed), descriptive URLs, multiple users with controllable privileges, access control and restrictions, and workflow tools (triggers). There are over 30,000 addons or modules to expand Drupal's functionality.