Core developers left over governance concerns with Miro. All core devs went with the fork.
Mambo/Joomla is a PHP-based content management system for building websites. It provides a web-based admin interface, template system, and extension architecture. In the mid-2000s, it competed directly with WordPress and Drupal as one of the most popular ways to build a website without writing code from scratch.
Mambo started life in 2000 as a product of Australian company Miro Construct Pty Ltd, headed by CEO Peter Lamont. It grew into one of the most popular open source content management systems of the early 2000s, winning multiple awards and building a vibrant community of developers and designers. But there was always a tension at its core: the software was open source, but Miro held the reins.
The powder keg ignited on August 8, 2005, when Lamont incorporated the Mambo Foundation without consulting the development team. He appointed himself President of the Board, bypassing the two developer representatives—Andrew Eddie and Brian Teeman—who had been elected to the Mambo Steering Committee. The Foundation's charter included provisions the developers felt contradicted previous agreements and violated core open source principles. It was governance theater: the appearance of community control with none of the substance.
Nine days later, on August 17, 2005, the entire 20-person core development team walked out. With help from the Software Freedom Law Center, they formed Open Source Matters, a proper non-profit. Lamont fired back with a public rebuttal titled 'The Mambo Open Source Controversy—20 Questions With Miro,' but it was too late. The community had already voted with their feet.
The team announced the name 'Joomla'—a phonetic spelling of the Swahili word 'jumla' meaning 'all together'—on September 1, and shipped Joomla 1.0 just fifteen days later. It was one of the fastest fork-to-release turnarounds in open source history.
Joomla went on to become one of the three dominant CMSes alongside WordPress and Drupal, powering millions of websites. Mambo, stripped of its entire development team, limped along until 2008 before going dormant. Ironically, even some of the Joomla founders—Eddie, Teeman, and Mitch Pirtle—eventually departed Joomla within its first two years, suggesting governance tensions are a recurring virus in CMS communities.
Mambo created by Miro Construct Pty Ltd in Australia
Peter Lamont incorporates Mambo Foundation, appoints himself President without consulting developers
All 20 core developers fork Mambo, form Open Source Matters with SFLC help
Fork name 'Joomla' announced publicly
Joomla 1.0 released
Mambo development effectively ceases
Joomla became one of the 'big three' open source CMSes, powering tens of millions of websites and spawning a massive ecosystem of extensions and templates. It demonstrated that when a corporate sponsor alienates its entire developer community, the community can walk away and take the project's momentum with them.
The fork also established a template for CMS governance disputes and influenced how other projects structured their foundations. The formation of Open Source Matters as a non-profit set a standard for community-governed open source projects.