Setting Windows free
Windows 9, aka Threshold, isn't the only Windows on the horizon. Windows 8.1 with Bing, a low-cost version of Windows for small tablets and laptops where OEMs set the default search as Bing (users can still change the default if they wish), is spearheading a wave of low-cost Windows devices such as Toshiba's £103 Encore Mini.
That puts Windows head-to-head with small Android tablets, Apple's all-conquering iPads and Google's increasingly compelling Chromebooks.
One of the most compelling Windows 9 rumours is that Microsoft will do what it did with Windows 8.1: make it available for free.
According to analyst firm Net Applications, the Windows 8.1 update has gained significant market share very quickly: 53% of PCs running Windows 8.x are running the most recent version just seven months after it was introduced. Windows 8's uptake was significantly slower.
Writing in Computerworld, Gregg Keizer suggests that Microsoft may be considering making Windows 9 a free upgrade not just to Windows 8.1, but to Windows 7 too.
If he's right, the effects could be significant: just imagine all the low-cost devices sold with Windows 8.1 with Bing and the corporate computers sticking with Windows 7 all upgrading to Windows 9.
A bold new revenue model
It wouldn't be overnight, but Windows 9 would accumulate significant market share much more quickly than if it were a paid-for product.
That makes Microsoft's job easier, with the bulk of its customers on the most secure version of Windows to date, using its most recent web browser, able to access its Windows Store and using Microsoft's various online services.
That market share would be in the consumer sector at first, because of course businesses are more careful and tend to upgrade much more slowly, but the corporations would eventually get on board too.
In that scenario the money Microsoft would lose on OS sales would be more than compensated by the money it would make from selling services. Perhaps the Threshold codename is prescient: Microsoft could be on the threshold of something very interesting indeed.
