Windows 8, Microsoft reported yesterday, has sold 40 million Windows 8 licenses in its first month of retail. That’s an indisputably huge number, outpacing even Windows 7 sales at launch. But it’s also a number that raises as many questions as answers.

It’s easy to forget that the vast majority of Windows 8 licenses Microsoft sells isn’t direct to consumers. It’s to Lenovo, HP, Dell, and all of its other hardware partners, who then go on to sell (or not sell) those devices to real human people. So how many copies of Windows 8 are on family room desks, and how many are collecting dust on an electronic store’s back shelf?

There had already been a handful of Microsoft Stores scattered across the US, but the company made a huge self-branded retail push this autumn to help boost its Windows 8 launch. So how many of those license sales are directly attributable to Microsoft’s 65 North American shopping locales?

The success and failure of Microsoft Stores obviously can’t be measured just in revenue; their main purpose is to familiarise people with a distinctly unfamiliar desktop platform, and to evangelise Microsoft’s future-forward Surface hybrids. But remember that in 11 short years, Apple transformed a similar branding opportunity into the most lucrative retail operation in the world. Early strength from Microsoft Store sales could bode extremely well for Ballmer’s band company going forward, and could see them roll the same format out around the world.

One of the driving factors behind that big number is price; it only costs £25 to upgrade to Windows 8 Pro right now, and it’ll stay that cheap through January. A comparable upgrade from Vista to Windows 7 cost more than twice that.

That cut-rate pricing is smart for Microsoft, both because Apple OS upgrades have gotten so cheap and because it helps ensure strong sales figures out of the gate. But what happens when the price goes back up?

Despite any and all reservations, the most remarkable thing about Windows 8 licenses jumping out ahead of Windows 7 licenses is that you had to upgrade to Windows 7. Its immediate predecessor, Vista, was just that bad. There’s no such incentive with Windows 8; Windows 7 remains rock-solid, no one’s still on Vista, and if you’re on XP, well, you probably forgot that you even own a computer. Not only that, but Windows 8′s design overhaul—as much as we appreciate it around these parts—can be actively intimidating.

So who’s upgrading, who’s converting, and what does that mean for Windows 8′s long-term chances?

Microsoft also announced that 1,500 PCs and tablets have been certified for Windows 8, but didn’t give any granular detail into which had actually been successful. Forty million licenses is a big number no matter how the pie is sliced, but it would be in Microsoft’s long-term favor if touchscreen devices—the kind that Windows 8 was built for—were gaining traction. Unfortunately, according to recent comments by the CEO of Asustek to All Things D, that’s not the case.

So yes, Windows 8 is off to a strong sales start. But until we find out some of the numbers behind the numbers, it’s nearly impossible to tell what that means exactly for Microsoft, for you, and for the future of PCs.