Check out this article in Computerworld regarding recent Microsoft SEC filing:
1. Canonical (Ubuntu) and RedHat added to the Windows Client competitor list.
2. "Netbooks opened Microsoft to the possibility that some other OS could
get its grip on the desktop, however briefly," said Rob Helm, director
of research for Directions on Microsoft. "Now it's alert to that
possibility going forward."
3. Concerned about OEM partners, HP and Intel supporting Linux on their PCs..
Microsoft confirms linux on netbook threat and adds ubuntu redhat in SEC filing