b2/cafelog, more commonly known as b2 or cafelog, was the precursor to WordPress.b2/cafelog was estimated to have been installed 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, resulting in many of its most influential users migrating to WordPress. By October 2009 the Open Source CMS MarketShare Report concluded that WordPress enjoyed the greatest brand strength of any open-source content management system.
As of February 2017, WordPress is used by 58.7% of all the websites whose content management system is known. This is 27.5% of the top 10 million websites.