Wouldn't this be all about raising awareness for Microsoft?
Sure, the majority of people use a Microsoft product, but the majority of people use this Microsoft product because they just think that that's what a computer is. I'm thinking about my parents here. They don't have a clue about computers and, just like in the adverts, they think it is a case of "PC" or Mac. Not Windows or Linux or Chrome or OS X... They're computer is a Dell or whatever. There's no mention of Microsoft.
If Microsoft actually makes the general non-computer-savvy public know that they make this OS, as a separate entity from the actual computers they (the public) are buying, then Microsoft can make them aware of its features, of its productivity uses, of their software, of all of these things' links to their other products... Zune, Xbox, their mobile phone OS... In this way, they are very much a similar company to Apple.
What i imagine Microsoft's aim is, is to make people aware that they actually make an OS. That Windows isn't just something thrown into, and made as part of, every computer that's churned out. That this OS has features and uses.
Going to their ad campaigns, "I'm a PC and i do this..." etc. That was a stupid mistake for them to make - but perhaps one they had to since their only other choices were to remain quiet or talk about an OS, Vista, that near everyone had written off. Even the shopper ads are silly, focusing on the hardware aspects they (Microsoft) have nothing to do with - again, this was really the only choice they had left at the time.
I'd say they need to (and they probably plan to) get away from that whole "PC" term and start using the terms "Windows", "Microsoft" and "OS", especially with Chrome on the horizon. For average Joe, Chrome may very well be the first glimpse of "It's a PC... but that isn't Windows...?". They will start selling THEMSELVES. Their own products and offerings. I'd imagine that Windows 7 will be the start of this, that this is where they're headed, and that these retail stores/galleries aren't as silly an idea as a few of you are making out. They could very well be setting themselves up as a proper competitor to everything Apple, just by letting people know that "Oh, an iPhone? But a Windows Mobile phone works with these Windows 7 features and Microsoft software/programs. An iPod? But with the new Zune HD you can use Microsoft's new music streaming software seamlessly. You can also use this on your Xbox".
Of course, there's also the possibility that Microsoft are lacking direction entirely and are just throwing out any ideas they can muster with retail stores/galleries being the most recent.
(Note, i am not someone who buys, or has any plans nor desires to buy any Microsoft product. But you have to be able to discuss things with an open and unbiased mind or your comments are just going to be dismissed as fanboyish, uninformed or lacking any real thought).