Microsoft patent promise not GPL compatible
What Microsoft intends to do with its OSP is to forbid sublicensability, which is one of the cornerstone for distributing GPL code. The OSP page on Microsoft website is pretty clear about it:
you acknowledge as a condition of benefiting from it that no Microsoft rights are received from suppliers, distributors, or otherwise in connection with this promise.
In the Frequently Asked Questions:
Q: Is this OSP sub-licensable?
A: There is no need for sublicensing. […]
What Microsoft intends to do is to forbid GPL implementations by casting some doubt with their patent licensing.
Maybe someone has time and energy to write a "Free Specification Promise".
