WordPress is a free and open-source content management system (CMS) based on PHP and MySQL. WordPress is installed on a web server that is either part of an Internet hosting service or a network host in its own right. The first case may be a service like WordPress.com, for example, and the second case could be a computer running the software package WordPress.org. A local computer may be used for single-user testing and learning purposes. Features include a plugin architecture and a template system. WordPress was used by more than 27.5% of the top 10 million websites as of February 2017[update]. WordPress is reportedly the most popular website management or blogging system in use on the Web, supporting more than 60 million websites.