Joomla is an open source content management system(CMS), which enables you to build websites and powerful online applications. It has many aspects, including its ease-of-use and extensibility which have made it the most popular Website Software available. Joomla offers flexibility on a page-by-page basis.
Joomla is built on MVC(Model-View-Controller) web application framework, with which you could create sophisticated add-ons that extend its power. These add-ons include Component, Modules, and Plug-ins. Because of the complexities that joomla incorporates in terms of features, it is the perfect tool to enable web and graphic designers to create something that is incredibly unique for their client.