Brian X. Chen, writing for Wired:
With brand new test facilities, Microsoft is taking on the duty of ensuring that touchscreens and sensors are calibrated properly, for example, and each hardware model undergoes software stress tests to catch bugs and system errors (see picture above). The end result should be getting very close to the same OS on smartphones made by different manufacturers. That in turn could mitigate the issue of fragmentation for third-party developers: They can effectively code the same app for a large party of devices without much tweaking.
This approach positions Microsoft somewhere in between Apple’s complete control over the hardware and software of its mobile devices, and Google’s (partial) control over only the software. I think it’s a sound strategy for Microsoft; a must, even, if they have any hopes of remaining a major player in the mobile space.