Joomla is a content management system (CMS), which enables you to build multi-user Web sites quickly. Many aspects, including its ease-of-use and extensibility, have made Joomla the most popular free and open source Web site software available. Joomla, which operates on top of a LAMP stack (Linux/Apache/MySQL/PHP-perl), is designed to be easy to install and set up even if you're not an advanced user. Many Web hosting services offer a single-click install, getting your new site up and running in just a few minutes.