Earlier quoted context omitted.
AFACT there is no clause in the Windows license that MS could invoke that would prevent you from entering a complete industry. Google's position is literally... screw with us, and if WebM catches on, you can't do video on the internet.
And that's why nobody sane will try to screw with them. Nobody wants to lose the ability to do video on the internet during next 20 (plus/minus) years.
I guess as long as Google is pushing the technology that "you" like they can do no evil.