LinuxMCE was at the outset a fork of Pluto's debian based Linux distribution for home automation. The founder of the LinuxMCE project, Paul Webber, contacted Pluto after seeing a demo of their software at a trade conference. The Pluto folks were happy to let Paul create his own Linux distribution using their foundation so long as he renamed the project. Since then LinuxMCE has moved from debian to Ubuntu (a debian based distribution), and is now moving from being primarily run by Paul alone to being a more open project all around.
BTW Pluto allowed us to import all their existing Wiki pages, including their Programmer's Guide. The information is largely accurate for LinuxMCE as well and we've updated many of the parts that didn't apply to us since then.
Read about the History of LinuxMCE for more expansive background information.