Joomla is an open source content management system for publishing contents on internet and corporate intranets. Joomla is developed in PHP and by default is backed by MYSQL database.

Joomla project started in 2005 as a result of a fork from another open source cms project called mambo. Joomla is modular in design and its features and functionalities can be enhanced and customized through plug-ins, components and modules.

Plug-ins are used to alter and extend the original behavior of a Joomla platform. For example the Wikibot plugin allows the author of a content to use "Wikitags" which will auto-create hyperlinks to Wikipedia articles when displayed

Components installed on a Joomla platform, on the other hands, are like applications running on the Windows platform. They can be developed by third party developers (i.e. Peerglobe) and get installed on a existing Jooomla site.

Modules are view snippets that get placed within a page in different positions. For example adsense or a calendar view are modules.