Open source businesspeople are frustrated that their business models is not bringing them enormous returns. Microsoft perceives the threat of open source and wants to neutralize it.
If “we’re all mixed source companies” then there is no real difference between Microsoft and, say, Red Hat. Microsoft wants merely to share its profit secrets with anyone who is interested in making money rather than political points.
Thus its well-timed release of Web platform installers which can get open source developers conversant with tools like ASP .Net, Silverlight, and the .Net Framework.