Som med tidligere udgivelser leverer Joomla! en samlet og let-at-bruge ramme til at levere indhold til websteder af alle slags. For at understøtte den skiftende natur af internettet og fremkomne webteknologier, krævede Joomla en grundlæggende omstrukturering af dets kernefunktionaliteter og vi brugte også denne omstrukturering til at simplificere mange udfordringer indenfor det eksisterende brugerinterface. Joomla 1.5 har mange nye funktioner.

In Joomla! 1.5, you'll notice:

• Substantially improved usability, manageability, and scalability far beyond the original Mambo foundations

• Expanded accessibility to support internationalisation, double-byte characters and right-to-left support for Arabic, Farsi, and Hebrew languages among others

• Extended integration of external applications through Web services and remote authentication such as the Lightweight Directory Access Protocol (LDAP)

• Enhanced content delivery, template and presentation capabilities to support accessibility standards and content delivery to any destination

• A more sustainable and flexible framework for Component and Extension developers

• Backward compatibility with previous releases of Components, Templates, Modules, and other Extensions