There's a powerful environmental argument to be made too. Given the choice between a computer that uses 10 watts, and one that uses 200, which would you choose? While America has long-been slow to wake-up to environmental questions such as this, for the rest of the world the answer is a no-brainer. Speaking as somebody who lives in Europe, where energy bills are high, I'll probably never buy a desktop computer again. With power supplies now typically pushing 500-1000 watts, they simply use too much juice. A notebook computer uses just a fraction of that power, and one of these new ARM-based netbooks will use so little power that it's practically negligible.

Now, it's no-doubt possible for Windows to run on ARM, which is after all a completely different architecture compared to x86. Microsoft certainly has the engineering expertise to make it happen. But it would be like converting a petrol engine to run on diesel. It's possible, but a little pointless. After all the hard work is completed you may be wondering why you even bothered.

It's not just Windows that would have be converted, of course--short of creating a messy emulation layer that probably wouldn't work well on these slower processors, key applications such as Office would also need to be ported too.

Linux run on ARM for years. That's the nature of Linux. It isn't locked down, either philosophically or practically. So when the manufacturers of the new ARM-based notebooks look for an operating system, there was virtually only one choice (Windows CE is a possibility but that's too strongly associated with restricted-functionality mobile devices).

In a weird kind of way, Linux has almost a virtual monopoly in the non-x86 marketplace. Microsoft simply aren't there.

Google

Microsoft has a problem, and it's this: Google. This is a battle for silverback supremacy in the jungle because, in reality, the two companies can easily exist alongside each other and be extremely healthy doing so. But this town simply ain't big enough for the two of them.

Google has always been an open source company. Its search engine has run on Linux since day one, and when it was looking for a platform on which to build its Android mobile operating system, it didn't hesitate in choosing Linux (imagine how unthinkable it would be had Google decided that it would use Windows CE instead; such a decision would have been greeted with hoots of laughter). Google has also made efforts to support Linux with its desktop products, such as Google Earth (even if the products themselves aren't open source).