http://openness.microsoft.com/blog/2015/04/21/microsoft-debi...
http://openness.microsoft.com/blog/2015/04/21/microsoft-debi...
1) porting Visual Studio to Linux.
2) porting Office to Linux, or
3) contributing to Wine, with the goal of solving long-standing issues with their (above) software - but hey they could contribute in other areas too, since Wine is far from complete (a USB driver/stack is much needed IMHO).
I won't believe in Microsoft "openness" until I see one of the three above.
Edit: the fact they're using this event mainly to promote Azure services rather than talking about differences/upgrading issues from debian 7 to 8 speaks of itself.
It would probably be easier to make a stripped-down, open-source version of Windows. Then they probably wouldn't have to port anything.