Well, it appears Microsoft is taking a bit of a page out of Apple's book and not allowing any browser other than Internet Explorer on Windows 8 for ARM PCs.

http://retro-box.net/blargh/2012/05/10/microsoft-bans-firefox-on-arm/

No. They're blocking Win32 APIs. This has been known about for some time.

Google and Mozilla are just throwing their toys out of the pram because IE10 on this platform uses Win32 APIs to be able to run in both Metro and Classic - they'd be restricted to just Metro.

Of course, that's the whole intention on Windows on ARM - to have everything running in Metro using WinRT.

Poorly researched article is poor.

- For one, Mozilla has it wrong. This isn't about restricting web choice, this is about restricting Win32 API's. Mozilla is perfectly able to write a gecko-based browser for the metro-UI.
- For another, you're totally wrong on the iOS portion. There are numerous non-WebKit based browsers on the app store, Apple doesn't restrict them. The best example of this is Opera, which is on the App Store with it's own engine.

This won't make it through court. As soon as the EU smells anything like that, they're going to punish Microsoft.

Senate Judiciary Committee is examining whether Windows RT, a version of Windows 8 optimized for ARM processors, runs afoul of any antitrust regulations.

A spokeswoman for the committee confirmed that staffers were looking into the issue, but said at this point, it was just exploratory and there are no plans for a public hearing.

Like the other versions of Windows 8, Windows RT will include two environments: the classic Windows interface and the more Windows Phone-esque Metro style option. In a Wednesday blog post, Harvey Anderson, Mozilla's general counsel, alleged that "Windows on ARM prohibits any browser except for Internet Explorer from running in the privileged 'Windows Classic' environment."

That, he said, means "Windows on ARM - as currently designed - restricts user choice, reduces competition and chills innovation."

Anderson said the topic is important because while ARM chipsets are currently used primarily in phones and tablets "in the future ARM will be significant on the PC hardware platform as well."

Google said in a statement that it shares Mozilla's concerns.

"We've always welcomed innovation in the browser space across all platforms and strongly believe that having great competitors makes us all work harder," Google said. "In the end, consumers and developers benefit the most from robust competition."

...The European Commission says it is aware of Mozilla’s claim, but the ruling applied to PCs only. This means that if Mozilla wants to push the issue, it will have to argue that tablets are still PCs. That said, there is the possibility that ARM-based PCs could pop up in the future — actually, that’s probably likely — so Microsoft’s going to have to figure out a defense of its position soon.

The US is taking the same "wait and see" attitude. According to...