WordPress is a free and open source blogging tool and a content management system (CMS) based on PHP and MySQL, which runs on a web hosting service. Features include a plug-in architecture and a template system.
WordPress is used by more than 18.9% of the top 10 million websites as of August 2013. WordPress is the most popular blogging system in use on the Web, at more than 60 million websites.
It was first released on May 27, 2003, by its founders, Matt Mullenweg and Mike Little, as a fork of b2/cafelog. As of February 19, 2014, version 3.8 had been downloaded more than 20 million times. The license under which WordPress software is released is the GPLv2 (or later) from the Free Software Foundation.