Hi Michael, How's it all going?
You claim Windows is the de facto platform in use in homes and schools. I would challenge you on that and I admit up-front I am being pedantic but then whats new!

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The most common digital device in use today is the mobile phone (out numbers PC at least 3-to-1) and on those devices Windows is definitely in a minority, Symbian probably still rules the roost here. Also many homes will have games machines - Playstations, Wii etc.. with their own proprietary OSs.
Now in terms of mobility and mobile computing then Windows is a minority device. The desktop or even laptop of the late nineties in which one OS ruled them all I think is passing as we increasingly have access to powerful devices that reflect our personal interest and are portable.
I don't hate Windows or MS in general, still use it regularly (but no longer primarily) and the new HTC is on my watch list as a possible buy. My first smartphone was an SPV and it was a very good device, with Windows as the OS. There are still things that it did that I miss.
You ask us to "think about supporting every device which enhances learning and teaching!" and I agree with you and in the digital arena that is a massive task, when you consider the multitude of devices available to today's learner; in schools, post-16, HE or lifelong.
This is where Windows is its own worse enemy. The MS marketing of the nineties was pretty much make the world Microsoft. If someone produce a great browser, it had to go and build one in, if some else produce a fantastic media player they had to build one in. It almost seems that there was an air of paranoia about it all. It has led of course to the massive and never ending anti-trust legal wranglings.
In the meantime the world has moved on. The web and the web application are increasingly viable option as interfaces to rich experiences and this has great potential for learning for all ages and groups. Web 2.0 technologies have moved us on and now on great frameworks we can customise and develop in ways which were only dreamt of a few years ago. The MS model of domination is out-of-date and for a mobile platform (where every byte counts) was never in date. I suspect we see similar problems for some of the monolithic VLE vendors in the near future as the world moves towards agile and rapid development.
In the last two years I think MS is starting to respond in a more interesting way and maybe we'll see an interesting renaissance for the company, perhaps similar to how IBM has reinvented itself.