A Content Management System, or a CMS for short, is a web-based application consisting of a central interface that allows easy content delivery and authoring. A CMS allows you to manage workflow, and collaborate with your team for creating web or blog content. Many Content Management Systems allow non-technical users to manage a website, and streamline publishing so you can have a rich array of content on your site with ease.
CMS allows:
• Creation of Fresh Content.
• Customisable Templates.
• Plugins and Widgets.
• Search Engine Optimisation (SEO) tools.
• Widely accessible and updateable.
The following CMSes are PHP-based, and use a MySQL database. The advantages of using such a CMS include portability, support and a large developer base with frequent updates and improvements.
Drupal:
A free open source content management system written in PHP and distributed under the GNU General Public License. Drupal is currently up to version 6.17, with working ongoing for version 7, a much anticipated release. Drupal's built-in functionality, plus the thousands of freely available add-on modules, provides developers with much-requested features:
• Easy to get started with.
• Open source PHP platform.
• Very active community.
• Only support coming from community rather than a company.
• One size fits all.
• Ability to add lots of content.
• Not great for Ecommerce stores.
• Plugins from many different developers.
• No interface to create and publish content – difficult for those non-technical users.
Joomla:

An open source content management system platform for publishing content as a Model–view–controller (MVC) web application framework. Joomla enables developers to build complex web sites and online applications. It is built upon PHP and MySQL. Joomla can be used to create:
• Inventory control systems.
• Data reporting tools.
• Application bridges.
• Custom product catalogs.
• Integrated e-commerce systems.
• Complex business directories.
• Reservation systems.
• Communication tools.
The Joomla CMS has a very large developer base, and its features include:
• User Management
• Media Manager
• Language Manager
• Banner Management
• Contact Management
• Polls, Search
• Web Link Management
• Content Management
• Syndication and Newsfeed Management
• Menu Manager
• Template Management
• Integrated Help System
• Web Services
• Extensibility
Installation of Joomla is much the same as with Drupal. Create a MySQL database, upload the Joomla package files to your web server, point your web browser at the installation file, and follow the on-screen instructions.
Wordpress:
WordPress is a hugely popular platform, with many websites and blogs alike utilising the CMS. With many thousands of Wordpress sites alive today, the software is supported by a large developer network.
Wordpress provides the following features :
• Simple and easy to use.
• Wealth of plugins.
• Security issues – very open to security risks due to open source nature and plugin compatibility.
• Great for blogs – Simple content management and easy to use text editor.
• Add-ons provide extra functionality and capabilities.
• SEO friendly.
• Great visual editor.
• Reliant on the community without official support.
• Great for blogging and content marketing purposes.