CMS stand for Content Management System. The basic purpose of CMS is to control whole website functionality from backend. CMS aim to avoid the need of hand coding, it allow the users to publishing, editing and modifying the content. CMS are often used to run websites containing blogs, news and shopings. Users can modify the functionality of CMS by adding different types of plugins and modules. There are many CMS written in php. Here is the top 5 PHP CMS.

1. WORDPRESS:

Wordpress is a free open source content management system (CMS) and blogging tool written in PHP and mySQL. The first version of worpress was released on 27-may-2003 by its founders Matt Mullenweg and Mike Little. It is the most popular and mostly used CMS, there are thousand of themes and plugin are available which extend its functionality and make it more smarts, wordpress community is also very large and more helps are aviable on internet.

ADVANTAGES:

1. Community is very large
2. thousand of themes and plugins available
3. User friendly backend. 
4. easy to understand.

2. JOOMLA: 

Joomla is award winning CMS written in PHP using OOP(Object Oriented Programming) technique for publishing web contents. It build on Model-View-Controller (MVC) architecture. Joomla is the second most popular CMS after wordpress. Till February 2014, joomla has been download over 50 million times, it has over 7,700 free and commercial extensions available on his official extension directory, and more are available on other sites.

ADVANTAGES:

1. secure
2. more then 7,700 extensions are available
3. active user community and nice documentation

3. DRUPAL:

Drupal is the third most popular CMS which is also free and open source, its means you can download and install many times you want, and can spread around your friends and society.  Its also have a large and active community of  630,000+ users and developers. Many of heavy websites including New York Observer, Popular Science and MIT are running on Drupal. Taxanomy module is a great feature in drupal which allows multiple levels and types of categories.

ADVANTAGES:

1. active community support
2. more then 6000 modules extend the functionality
3. commercial support from different companies.

4. SILVERSTRIPE:

Silverstripe is an object oriented php5 content management system, it is also based on MVC architecture. It is popular due the following features.
1. out of box template, support responsive design.
2. rich text editing
3. can embed videos from sites like youtube, slideshare etc.
4. drag and drop tree-based navigation structure.

5. EXPRESSIONENGINE:

Expressionengine is also a CMS written in PHP. Its backend is so easy to understand , programming skill is not mandatory to handle the backend. The base code of  Expressionengine is build by using codeigniter , which is their own open-source php framework. Like other CMS’S Expressionengine did’t have much add-ons and plugins, only 22 add-ons modules and little over than 100 official plugins are available.