To understand the controversy, you need a little bit of background about how Windows 8 on ARM tablets will work. (Windows 8 for ARM tablets, once called WOA, is now formally called Windows RT.)
Windows RT, like Windows 8, will include a Metro interface and a desktop interface, and some people call the desktop interface "Windows Classic." It's likely that most people won't run the desktop interface that often, because Metro is far better suited for touchscreen tablets.
Metro is a much more restricted environment than Windows Classic, and a variety of browser technologies and add-ins won't run in it. That's true in the traditional version of Windows 8 as well as the tablet version of Windows 8, Windows RT. In the traditional version of Windows 8, though, any browser will be able to also run in the desktop, taking advantage of certain features.
On Windows RT, though, only one browser will be allowed on the Windows Classic desktop -- Internet Explorer. Chrome, Firefox, and other browsers will be banned. And that's what has Mozilla and Google up in arms. (Or is that up in ARMs?)
Mozilla project manager Asa Dotzler, in charge of developing Firefox for Windows 8, claims in a blog post that this gives Microsoft an unfair advantage:
"Windows on ARM prohibits any browser except for Internet Explorer from running in the privileged “Windows Classic” environment. In practice, this means that only Internet Explorer will be able to perform many of the advanced computing functions vital to modern browsers in terms of speed, stability, and security to which users have grown accustomed. Given that IE can run in Windows on ARM, there is no technical reason to conclude other browsers can't do the same.Google agrees with Dotzler, telling CNet:
Why does this matter to users? Quite simply because Windows on ARM -- as currently designed -- restricts user choice, reduces competition and chills innovation. By allowing only IE to perform the advanced functions of a modern Web browser, third-party browsers are effectively excluded from the platform."
"We share the concerns Mozilla has raised regarding the Windows 8 environment restricting user choice and innovation. We've always welcomed innovation in the browser space across all platforms and strongly believe that having great competitors makes us all work harder. In the end, consumers and developers benefit the most from robust competition."Microsoft claims that it needs to restrict access to the desktop for security and performance reasons, and that's why only a few apps get access to it, notably IE and Microsoft Office.
I don't completely buy Microsoft's reasoning -- after all, on Windows 8 for PCs, other apps are allowed to run on the desktop. It may be true that Windows RT hardware will be more susceptible to performance slow-downs than traditional Windows hardware, because RT hardware will generally have slower processors and less RAM. That won't always be the case, though, because Windows 8 will run on netbooks, which typically have low-end hardware.
However, I also don't think that banning Chrome, Firefox, and other browsers from the RT desktop will make a difference to browser market share. There's not much of a chance that Windows 8 tablets will make significant headway against iPads and Android tablets. And of the people who do use Windows tablets, only a very small percentage would likely switch their default browser, even if they had a choice. So in terms of market share, not allowing Firefox and Chrome on the desktop will barely register as a blip.
As for user choice, it would certainly be better if Windows 8 tablet buyers had more than one realistic option in browsers. But limiting browser choice is likely to hurt Microsoft more than help it.