The right to fork is the second most-controversial aspect of the open source ideal.
Just as some people call the responsibility to share code a rip-off of intellectual property, they are liable to see forks as treason against the parent project.
But not always.
Josh Lowenson's introduction to Melody, a fork of open source Movable Type, reads like a friendly fork. Indeed Movable Type's Benjamin Trott has a quite-friendly introduction to the software right now on Movable Type's home page.
One reason for Trott's support of the Open Melody Software Group may lie in Movable Type's own history. It did not start as open source code. It began, a decade ago, as an early competitor to Blogger and Dave Winer's Weblogger.
Movable Type did not become open source until 2007, after WordPress had passed it by in many ways, proving the value of the open source model. In a way, Melody is Movable Type's effort to build community following the release of its software, something most projects do the other way around.
So while relations between Movable Type and Bryne Reese, the MT community manager heading Melody, do seem cordial, there is some serious business strategy going on here.
For Movable Type to advance against WordPress, it needs this fork to succeed.