A popular free open source content management and blog system platform. Based on PHP and MySQL, WordPress enables users to create sophisticated, professional-looking web sites and blogs. WordPress is available under the General Public License (GPL) version 2.0.
WordPress competes in the content management market with other services like Drupal and Joomla, and it currently powers more than 73 million web sites. WordPress also offers users an extensive selection of plug-ins and templates, or themes, to extend the functionality and customizability options of the platform.
Version 3.0 of WordPress introduced a new feature, WordPress Multi-User or WordPress MU, which makes it possible to create multiple blogs with a single installation of WordPress that can be administered from a centralized administration panel.