WordPress is the most popular Content Management System (CMS) and is currently being used on 73 million websites globally.

The platform itself is OpenSource which means there is no licensing fee for the WordPress software itself. Thousands of plugins and themes are available to extend the functionality of this popular CMS.   Licensing fees do apply to some of these plugins where many are free and might have more advanced feature enhanced versions available for a modest fee. WordPress is written in PHP and uses a MySQL database.  You might be surprised to know how many websites are built upon this powerful CMS.  As of this writing in 2017, a few noteworthy sites include: