Joomla! is a free open source website development and content management (CMS) platform.
Like other content management systems, Joomla! removes much of the technical aspect of setting up and running a website.
Some significant features:
Provides plugs ins and site modules to enhance websites and content.
Over 6000 extensions available.
Responsive templates adapt websites for various platforms, including mobile devices.
Permission levels restrict site user file access while giving site workers access to the files they need to do their particular jobs.
Support for different languages for different sites or site sections.
Supports polls, search and web link management and analysis.
Joomla! is based on Mambo, an earlier CMS, that was created by that software's development team. The development team created Joomla! to further and protect open source principles that they felt were being compromised.
In this video tutorial, learn how to use Joomla! to create a complete website in one hour: