Here's another useful snippet of information from the Windows 8 engineering team blog - if you want the ideal experience running apps in the Metro part of the OS, you'll want to run your monitor at 1366x768.
This isn't the minimum screen resolution, and the OS will work at other resolutions (above a certain point - more on that below), but it's the screen resolution the coders have kept in mind as the best-case scenario for displaying the new tablet-style Windows 8 apps.
So why care? Depending on your screen size, or screen resolution, you might find the app displays more info. That's because Windows 8 apps (some of them at least) can be designed to adaptively scale to fit your display.
The bigger your screen and the higher the resolution, the more information your app might be able to show - more weather reports, more stock prices, the full complement of buttons.
Microsoft picked on 1366x768 because it fits one app taking up the main part of the screen, and has enough width for another to sit "snapped" to the side.
There is also a minimum resolution - 1024x768. The basic upshot is that you won't be able to run Metro apps if your screen runs below this. There is the odd netbook user out there who's pretty cranky about it, though there is a workaround for registry fiddlers. (Microsoft argues that their data shows a small percentage of Windows 7 users in this category).
Full screen and DPI
This could all be seen as an upshot of the move to incorporate the millions of tablets out there with an OS once previously built specifically for desktops with big monitors. The result is a move away from the thing Windows is famous for - programs that sit in boxes that can be resized to any dimension and dragged all over the screen.
Running Windows 7 or earlier, you can expand and minimize program windows to your heart's content. But in Windows 8 (within the Metro part at least - remember, the classic desktop is still there in Windows 8), apps are designed to run full-screen or "snapped" to the side of the desktop.
So what about your screen resolution? The Windows 8 engineering team blog has gone into depth on how to make these full screen apps scale to fit the different screens and Apps change to fit different screen sizes - Adaptive - layout changes to fit more or less in.
You've probably experienced that moment when first loading program or a new screen or a small laptop and everything looks wrong. Tiny text, icons you can't see etc. We imagine the potential for this is going to multiply with tablets entering the mix. To get round this, Windows 8 will scale apps to fit screens - there's a bunch of detail here about how, but in summary, the idea is to keep Metro buttons and icons and text the same size, whatever screen DPI you're running.
As we mentioned earlier, adaptively scaled apps can make better use of bigger screens by actually using the space for more info. Games will be treated differently, with letterboxing.
Note that this scaling will support resolutions up to 2560x1440.
Note that this isn't continuous scaling - ie. which would make it theoretically possible to drag your Windows however big you want them. As the blog post explains, Microsoft has chosen three percentages to scale to.
Who is using what screen resolution in Windows 7. (Source: Building Windows 8 Blog)
The blog states: "First, on laptops (over 75% of PCs purchased by consumers) most applications are run maximized all the time - this makes sense given the real estate available and the design points of most interfaces and web sites. Second, on large screen displays, most windows are sized to a reasonable number of rough dimensions primarily because most programs do not support “infinite” scaling."
"It is important not to look at this in isolation as "no more resizable windows," but rather as part of a larger effort to provide a wider choice of screen sizes, resolutions, and densities, where developers can know their apps will work and consumers can be sure that their apps are compatible with their hardware. We do this so you don't have to compromise by using software that isn't fully functional or only getting to choose among a small set of screen sizes (and price points, power consumption, etc.)"
Pros and cons
Meanwhile, as Microsoft points out, Apple can get away with introducing the Retina display on the new iPad because it's just one new screen configuration. There are no other screen resolutions to deal with.
It's a classic case of where the open nature of the PC platform is both its strength (more screens, more devices, more choice) and its Achilles heel.