Wordpress for Beginners 2016 WordPress is an open source content management system (CMS) that is free and completely based on PHP and MySQL. It is normally installed on a web server that is part of the internet hosting service or on a network host. The main features of this service include an architecture that works with plugins and templates that are used to develop sites. It is used by approximately 20% of the top websites on the internet as of January 2015. It is essentially considered to be the most popular blogging system that is being used on over 60 million websites.