WordPress is a free and open source blogging tool and a 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 blogging system in use on the Web.
It was first released on May 27, 2003, by founders Matt Mullenwegand Mike Little as a fork of b2/cafelog. As of December 2011, version 3.0 had been downloaded over 65 million times.
b2/cafelog, more commonly known as simply b2 or cafelog, was the precursor to WordPress.b2/cafelog was estimated to have been employed on approximately 2,000 blogs as of May 2003. It was written in PHP for use with MySQL by Michel Valdrighi, who is now a contributing developer to WordPress. Although WordPress is the official successor, another project, b2evolution, is also in active development.
WordPress first appeared in 2003 as a joint effort between Matt Mullenweg and Mike Little to create a fork of b2. Christine Selleck Tremoulet, a friend of Mullenweg, suggested the name WordPress.
In 2004 the licensing terms for the competing Movable Type package were changed by Six Apart and many of its most influential users migrated to WordPress. By October 2009 the 2009 Open Source content management system Market Share Report reached the conclusion that WordPress enjoyed the greatest brand strength of any open-source content-management systems.
Courtesy to : Wikipedia