WordPress is a free and open source blogging tool and content management system (CMS) based on PHP and MySQL. It has many features including a plug-in architecture and a template system. WordPress is used by over 14.7% of Alexa Internet’s “top 1 million” websites and as of August 2011 manages 22% of all new websites. WordPress is currently the most popular CMS in use on the Internet.
It was first released on May 27, 2003, by Matt Mullenweg as a fork of b2/cafelog. As of December 2011, version 3.0 had been downloaded over 65 million times.