At times like these, when proprietary software companies and turncoats from within the FOSS sphere are actively engaged in a battle to dominate standards, it is good to have a company like Red Hat on-side.
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But looking at Red Hat's reaction to the recent Microsoft announcement about interoperability, it is easy to see that the North Carolina-based company is not a one-dimensional firm. Few companies would react to a statement from the biggest and most powerful proprietary software company - and one which is actively trying to steal its lunch - with anything resembling these words: "Red Hat regards this most recent announcement with a healthy dose of skepticism (sic)."
--Bill Gates (Microsoft's CEO at the time)
So, a software created under the Microsoft Open Premise may not be licensed under a free license, if it violates, or may violate a Microsoft patent. In other words, one should excercise extra care when FOSS-licensing such a software. MOP is only partially compatible with the free licenses, and it could be safer to regard it as generally incompatible with them.