Interesting article on GMSV.
Typically, the only way to get a good look at Microsoft’s source code was via leak or the company’s “Shared Source” program. No longer. On Monday, Microsoft released some of its code (the Windows Installer Xml (WiX) toolset ) under an open-source license, and posted it on SourceForge. Rob Mensching, the Microsoft employee behind the unprecedented code release, commented on it in a post to his Web log. “After four and a half years of part-time development, the WiX design (and most of the code) matured to a point where I was comfortable trying to release it externally,” Mensching explained. “So, last October I started looking for a means to release not only the tools but the source code as well. I thought GotDotNet was the place. However, at that time, none of the existing Shared Source licenses were flexible enough to accept contributions from the community. Then, in February, I was introduced to Stephen Walli who was also working to improve Microsoft’s relationship with the Open Source community. Fortunately, Stephen was much farther along than I and had the step-by-step plan how to release an Open Source project from Microsoft using an approved OSS license. Today, via WiX on SourceForge, you get to see the results of many people’s efforts to improve Microsoft from the inside out. I’m not exactly sure what is going to happen next but I’m sure there are quite a few people who are interested to see where this leads. Personally, all I hope is that if you find the WiX toolset useful then you’ll join the community and help us improve the toolset.”