1. WordPress

It was first released on May 27, 2003, by founders Matt Mullenweg. WordPress is a free open source blogging tool and a Content Management System(CMS) based on PHP and MySQL. WordPress is currently the most popular blogging system in use on the web.

2. Joomla

Joomla is a free and open source Content Management System for publishing content on the world wide web. Joomla is written in PHP uses object oriented programming techniques and stores the data in MySQL.

3. Drupal

Drupal is a open source content management framework written in PHP. The standard release of Drupal, known as Drupal core, contains basic features common to content management systems. These include user account registration and maintenance, menu management, RSS feeds, page layout customization, and system administration.