WordPress
WordPress is free, open source publishing software that can be installed locally on a web server and viewed on a proprietary web site or hosted in the cloud and viewed on the WordPress web site.
In 2001, Matt Mullenweg and Mike Little co-founded WordPress, launching it in May 2003 with the help of several core contributing developers. At that time, WordPress was merely a free blogging forum for users. Since then, WordPress has evolved to be a full content management system with widgets, plugins and customizable themes. WordPress is licensed under GPLv2, which lists terms and conditions for copying, modifying and distributing free software.