I picked this up from Microsoft's Shared Source Initiative website. A lot of people have this idea that open source means Linux and hence its a war between the open source community and Microsoft. As the following text clearly speaks out, it is a combination of the two that is to be desired.
Microsoft has been learning from the OSS community regarding the benefits of deeper collaboration and increased transparency leading to better communication with customers. We believe the most effective pathway for a commercial software company is to strike a balance between investing in research and development and the release of intellectual property assets in the form of source code for both reference and collaborative purposes.
The increased competition resulting from the proliferation of OSS has been constructive for the industry as a whole. The implications of OSS within multiple market segments are causing organizations to figure out what is most important to them. It has placed a higher premium on innovation and a drive to deliver greater value for lower costs. The big winner in this equation has been the software consumer, whose choices have increased dramatically.
The Shared Source Initiative is the manifestation of these factors within Microsoft. With more than 80 source code offerings being used by more than two million developers, Microsoft is looking to apply the best of open source while helping its customers avoid many of the model’s pitfalls. There is no one, correct way to create software. The ecosystem as a whole will benefit from a rich tapestry of development, business, and licensing models.