It must be maddening to believe you command developer loyalties and lead legions worldwide, then watch developers flock to the Linux kernel. Maddening, that is, if you're Microsoft. Why does Microsoft say its patents cover Linux, while at the same time reaching out to other open source code projects? It's the Linux kernel development process.
Imagine you're Microsoft and you've spent years struggling to get Windows Server 2008 out the door and will be struggling afterward to add server virtualization? Then along comes Linus Torvalds and his merry band and they add KVM to the Linux kernel over the course of a few months, release a new kernel for review every 2 to 3 months, and attract thousands of developers interested in the new features. Linux had both VMware and Xen hypervisors running on it just fine. Now it's got another one freely available inside the kernel. It must feel in Redmond like Linux steals from the rich to give to the poor.
http://www.informationweek.com/blog/main/archives/2007/11/why_microsoft_r.html