The irony is that Joomla! is actually Mambo. It was a direct descendant. But because of that domain mishap and the branding shift, Mambo became a ghost town, and Joomla rose to become the world's most popular Content Management System (a title it held for several years before WordPress eventually overtook everyone).
Allowed users to expand core setups via third-party extensions, components, and templates. mamboserver.com