Open Source Matters is the non-profit organization that provides organizational, legal and financial support for the Joomla! open-source project. It is responsible for all project activities that are not the responsibility of the production working group or the community working group. These include areas such as operations management, events, the shop, marketing, and public relations in addition to brand management and licensing issues.

Written by two long time Joomla! project contributors with years of experience building Joomla! websites, the book explains website design and structure and how to use Joomla! to create an effective online presence.
The Official Joomla! Book offers an explanation of the Joomla! project and community, with information on the official sites, how to use them, and the many ways people of all experience levels can become participants and contributors. The book provides helpful step by step instructions and direction for those without any experience in creating websites, as well as tips and information for experienced web administrators and creators.

Joomla extensions help extend the Joomla websites' ability. There are five types of extensions for Joomla!: Components, Modules, Plugins, Templates, and Languages. Each of these extensions handles a specific function.

Over 7,700 free and commercial extensions are available from the official Joomla! Extension Directory, and much more are available from other sources.