I am usually not the one to blow the free software horn (being a staunch believer of non-copyleft licenses such as the Apache License) and the geek in me likes this announcement. I also don't hold a grudge against Windows, I think it is a fine system for most people. However, Windows seems very much contrary to the goal of the Raspberry Pi: providing a device for children to tinker with and educate themselves. Althou…
While having software that's open source on the Pi would be awesome, what would be even more awesome is tonnes of apps on Github that are easier to write for the Raspberry pi to allow it to do more than it can currently such as Media Streamers & Servers of all sorts with tonnes of forks.
For what its worth, this is giant leaps forward for Microsoft and vastly uncharacteristic of what they're used to. It shows that they're hell bent on driving their platform through developers. The typical R-pi purchaser is a dev after all.