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 26.4% of the top 10 million websites as of April 2016. WordPress is reportedly the easiest and most popular website management or blogging system in use on the Web, supporting more than 60 million websites.
Joomla is a free and open-source content management system (CMS) for publishing web content.
It is built on a model–view–controller web application framework that can be used independently of the CMS.
Joomla is written in PHP, uses object-oriented programming (OOP) techniques (since version 1.5) and software design patterns, stores data in a MySQL, MS SQL (since version 2.5), or PostgreSQL (since version 3.0) database, and includes features such as page caching, RSS feeds, printable versions of pages, news flashes, blogs, search, and support for language internationalization.
Drupal, a free and open source content-management framework written in PHP and distributed under the GNU General Public License provides a back-end framework for at least 2.2% of all Web sites worldwide – ranging from personal blogs to corporate, political, and government sites. Systems also use Drupal for knowledge management and for business collaboration.
MODX (originally MODx) is a free, open source content management system and web application framework for publishing content on the world wide web and intranets. MODX is licensed under the GPL, is written in the PHP programming language, and supports MySQL and Microsoft SQL Server as the database. It was awarded Packt Publishing's Most Promising Open Source Content Management System in 2007.
Concrete5 is an open source content management system (CMS) for publishing content on the World Wide Web and intranets. Concrete5 was designed for ease of use, for users with a minimum of technical skills. It enables users to edit site content directly from the page. It provides version management for every page, similar to wiki software, another type of web site development software. concrete5 allows users to edit images through an embedded editor on the page.