Open-Source CMS Mambo has forked in a another project called Joomla after some disagreements about how Miro International wanted to create a Mambo Fundation. The clash roots are explained a little bit in the following articles:

• Open-source Mambo project faces rift by Stephen Shankland, ZDNet Australia (23 August 2005 )
• Joomla is the New Mambo by Mike McEwan (26 September 2005)

It seems that some of the main developers have already join Joomla. Jomla 1.0 has already been released. It's a fork from Mambo v4.5.23 with some improvements. See also Joomla roadmap.

This blog note has been written after a discussion (in French) started by Jérôme on Baccou Bonneville Forum.