• Source code is completely free.
• A large and healthy user and developer community.
• Provides a basic level of content approval for registered users.
• Online help.
• Page caching mechanism to improve performance on busy sites.
• Trash manager
• Advertising management (banners, etc).
• Media (images, documents) upload and management.
• Content display scheduling.
• Content syndication (RSS).
• Search engine friendly (SEF) URL's.
• Internationalisation (interface translation).
• Content macro language (aka mambots).
• Advanced and separate system administation system.
• Advanced package/addon/template deployment system.
• Simple but powerful template system (written mostly in HTML, no complex templating syntax to learn, just a couple of PHP functions to include).
• Heirarchial user access groups.
• Basic visitor statistics.
• Multiple WYSIWYG content editor support.
• Simple polls.
• Content voting/rating system.null

Veel meer vrije Joomla! extenties zijn beschikbaar op internet. Enkele extenties zijn:

• LDAP authenticatie
• Uitgebreide gebruikers profielen
• Forums
• Media gallerijen
• Document/download beheer
• Templates
• Agenda/ calendar
• Webshop
• en vele, vele anderen...