The product key is actually embedded in the BIOS. Hurrah for that -- sort of. The good news is that during a reinstallation of the OS, the installer will automatically recognize the product key and use it for activation and installation. It's tons easier than having to type the string in.
Microsoft needs to update its FAQ for installation; it still mentions the sticker.
There is a lingering question, though. What happens if you want to install a different version of the operating system on a computer? Granted, there are now only two different versions, but what if you bought a laptop with Windows 8 and have a copy of Windows 8 Pro that your purchased separately?
During installation, the software will automatically use the BIOS key. So how do you get an upgrade to Pro? Indeed, you can do a Windows Anytime upgrade directly on the PC, but that can be -- depending on how you acquire the software -- more expensive than buying an upgrade separately.
Still, it's convenient to do an Anytime Upgrade directly from the PC. It's possible that Microsoft is just encouraging folks to opt for this route. We're sure -- or at least, pretty sure -- there's a way around this conundrum, but don't have the details as yet.