[InclinedPlane]

I don't think it's a huge shift as much as it is getting back to its roots. MS got its start by being the company that supported the PC as an open platform. Anyone could build a PC, any individual, any OEM, and put DOS or Windows on it. And anyone could write an app to run on DOS or Windows. For the time it was a remarkably free wheeling and open system, especially compared to what other companies like Apple was doing. And let us not forget that it was the success and growth of the open PC which made it possible for linux to come along and put itself on the same hardware. MS has certainly been guilty of various unfair business practices from time to time, and from trying to use its power to gain unfair advantage in the market, but for the most part I think that behavior tends to be the exception over Microsoft's history. Most of the time they are trying to pull customers and developers to them by offering a good platform and at some times even facilitating their own competition. In that regard, embracing open source is very much in keeping with that spirit, updated to reflect the new norms for what openness means today.

[Rapzid]

Sure, you could choose your hardware as long as you were running Windows. This is a new, different type of choice that MS is backing. ASP.NET(and MVC) vNext is goingt to be tested against mono. And mono represents code running on non-Windows platforms. I certainly view this as a shift; how large a shift is rather subjective.