This is something that I have been pondering for some time and which you probably can only "understand" if you use the Magic Trackpad. Let me start this way: I bought the Trackpad some time ago (Snow-Leopard?) but it did not "click". A few weeks ago, I tried again with the Mac-native configuration and more emphasis on the multi-Desktop and Launchpad/Mission-control concept of Lion and it works *really* well. In fact, my magic mouse is now gone from my Desktop. So lets take a look at Metro: Most UI try to give a unified "concept" on what you are working on: Most times it is a "Desk" on which different layers of "Tool" is stacked. Take iOS: you "open" an App in iOS and it is put "atop" the Desktop, you "drill down" to siri or "pull down" a curtain of information. I think MS is trying to change the metaphor more to an "endless Paper" on which you work instead of the Desk which you switch (in iOS you jump from one "Desk" to another). Think of a Paper "under" the screen that you can move like you do with some Applications (Graphics/Mindmaps) on the Mac or on iOS. This "endless Paper" really only works with touch/multitouch and that is why IMHO Metro looks so horrible to a lot of people right now who are basically "trained" on a mouse/keyboard combination but IMHO this may be a "good" Design for PCs that use (Multi)Touch: Smartphones/Tablets/LAPTOPS/ and PCs with Trackpads. That said, MS seems to bet a lot on that most consumers will switch to a touch aware device with their new devices (Laptops) that run Metro. The point I try to make is, that Metro seems to be tailored towards touch-input: for better or for worse. But the "concept" of Trackpads on PCs is sound... the question is: will the consumer go along and ditch the mouse?