A Content Management System ( CMS ) is used to add, edit, and delete content on a website. For a small website, such as this, adding and deleting a page manually is fairly simple. But for a large website with lots of pages like a news website adding a page manually without a content management system can be a headache. A CMS is meant to ease the process of adding and modifying new content to a webpage. The pages content are stored in database, not in the file server. HTML and other scripting language are not necessary to operate a CMS, though having them will add more advantages. Since we had looked here list of Open Source PHP Content Management Systems so that readers who don’t have strong PHP knowledge can easily create their website using free and open source CMS.
WordPress
WordPress does a pretty good job as a CMS, making it easy to maintain your site, and update your content. Initially it was designed as a blogging platform. However, it slowly become popular and can be customized into a powerful CMS with some tricks and plugins.
Drupal is a free and open source modular framework and Content Management System (CMS) written in PHP. It is used as a back-end system for many different types of websites, ranging from small personal blogs to large corporate and political sites.
Joomla is an award-winning content management system (CMS), which enables you to build Web sites and powerful online applications. Many aspects, including its ease-of-use and extensibility, have made Joomla the most popular Web site software available. Best of all, Joomla is an open source solution that is freely available to everyone.
Frog CMS simplifies content management by offering an elegant user interface, flexible templating per page, simple user management and permissions, as well as the tools necessary for file management. 5. SliverStripe SilverStripe is a PHP CMS built with Sapphire framework, and it uses MVC design pattern. you can view example sites that built with SilverStripe from the official webpage. 
Mambo
Mambo is a full-featured, award-winning content management system that can be used for everything from simple websites to complex corporate applications. Mambo’s “power in simplicity” also makes it the CMS of choice for many small businesses and personal sites. Although some Mambo sites had already migrated to Joomla, but i think i should include Mambo as it is still a great CMS.
TYPOlight now called Contao. TYPOlight is a PHP 5 CMS and it has a lot of features such as live update, cross-browser CSS framework generator(IE7 compatible), templated based front end output, use Ajax and Web 2.0 technologies.
Concrete5 is an open source content management system with simple administaror interface. It enables users to edit site content directly from the page. This makes the platform easy to use with a minimum of technical skills. 
Textpattern
Textpattern is an open source content management system.its aim is to be a general-purpose content management system suitable for deployment in many contexts. Textpattern is written in PHP using a MySQL database backend .
Symphony is a CMS that uses XML/XSLT as its templating language. Symphony lets you customize anything you like, from the website’s URL structure to your publishing environment. For a non programmer, this CMS might be complicated to learn.
MODx is both a PHP application framework and content managenemt system. MODx is the first free PHP CMS to offer an API that fully supports Web 2.0 Ajax technology. It is SEO friendly CMS, and allows you to configure the meta content for each page.
CMS Made Simple helps experienced web developers and designers to create sites of power and beauty in a fraction of the normal time, avoiding hours of coding and allowing your clients to update their own sites with a minimum of fuss. CMS Made Simple puts the power of a modular and extendable content management system at your fingertips. And best of all, it’s free!
Jojo Open Source CMS offers a fair bit of functionality out of the box, that other paid or free CMS systems don’t have, or require hacking to have. JOJO CMS have some feature, like Multi-site install, Image Handlling, SEO friendly CMS and Plugins.
Chyrp is a blogging engine designed to be very lightweight while retaining functionality. it uses Twig as the templating engine. It is powered by PHP and has very powerful theme and extension.
Elxis is powerful open source content management system. It has unique multi-lingual features, it follows W3C standards, it is secure, flexible, easy to use, and modern. The development team, Elxis Team, paid extra attention to the optimization of the CMS for the search engines and this lead to high performance of all elxis powered web sites and to high ranking in search engines results.
Habari is a highly recommended open source blogging platform. It is being written specifically for modern web hosting environment, and uses modern object oriented programming techniques.
ImpressCMS is a community developed Content Management System. It is highly scalable and is extremely useful for managing online communities.
Exponent uses an intuitive and flexible content editing system that allows website pages to be edited on the page as it is displayed. You can download modules and themes from the official website too!
Mia CMS is a fork of the Mambo CMS. It has a powerful and extensible third party entension system, and also a flexible site theming capabilities. MiaCMS supports OpenID and can consider to be a stable and mature CMS.
NanoCMS is a php open source, gpl licensed flat file content management system. It does not use a MySQL database and is ideal for small websites. It is a very small package (hence the nano part).
