On the other hand, if I go to Delta's website to see my flight information, only Delta really knows I did so
Actually your gateway and every hop along the way knows you were on Delta's site. If your traffic wasn't SSL-encrypted, they have the ability to even reconstruct the pages as you saw them. Somebody on your LAN with a packet sniffer could also do that. Your ISP essentially knows just about everything you do.
So? That's because there's a practical need in order to get the traffic where it's going. That doesn't mean Microsoft has any reason to know where you go as well.
I can't think of a reason that a protocol couldn't be developed that scanning apps would implement
I can't either. But who will operate the service for free? Even a consortium would have to make money in some way to keep the service up. Or if the government runs it, then the tax payers pay for it. In the current model, the guys that showed initiative (by creating the service and the apps) reap the reward (profit), the businesses/individuals who can gain from the service will pay for it directly, and eventually consumers will pay for it (indirectly) in the cost of goods (same as any other form of advertising). The enterpreneur made money, business got done, consumers got a service. That's as it should be. If consumers don't use the service, businesses won't see the value, and MS won't get paid. That's also as it should be.
I fail to see what this model offers over QR Codes as used in Japan. QR Codes can contain a fair amount of data encoded in the barcode itself - enough for small images, or plenty of text. Those barcodes cost nothing to maintain once they're out there. If needed, the barcode can contain a URL, where more data can be provided. Most organization which would want to distribute these barcodes in the first place have their own webspace available, where they could easily host the content without having to pay extra to a third party. For those without, there's no technical reason a third party which did nothing but store data for these URL barcodes couldn't exist. Or multiple third parties, and let the free market determine pricing, rather than grant Microsoft the monopoly on it because they decided to reinvent what's already been done perfectly well in other parts of the world.
Essentially; what is Microsoft's role in this? Is it a critical role (you *need* the centralized server for some reason), or are they creating a false market segment?
They appear to have solved a problem that nobody seems to have solved adequately so far. All existing solutions either fail to associate rich content with the tag, or score poorly on the pattern recognition front, and fail miserably in adverse conditions. This solution still has the drawback of requiring net access -- but if you have that, it's the best solution by far. So Microsoft's role has been to do the research into creating the tag format, developing and testing the scanning apps, getting OEMs and partners to adopt the technology, providing the service. They have not done this out of the goodness of their heart -- they're in the technology business, and they see this as a business opportunity. It's not a false market or a real market or anything in between. MS wants your business, and they're working to earn it -- same as any other business.
As above, this adds nothing over what could already be done with existing technology. Having lived in Japan for a year, I can tell you that reading QR Codes on a cellphone is even simpler than point-and-click. You just point, and before you would have even pressed the button to tell it to read, it's already recognized the barcode and read the data. Works perfectly in all sorts of lighting conditions.
I mentioned a couple of uses such as printing a tag on your business card that work contacts can just scan to import your info
Already common with QR Codes in Japan, just encoding the data in the barcode itself. No need for any network access.
or "scan here for arrival/departure info" at the aiport. Out of 170+ responses on this story, there were only 2 other suggested applications. One was to put a tag next to exhibits in a museum so you can scan it and get more detailed information than what they're able to physically display -- very cool idea.
Again, this is perfectly doable with well-developed technology that doesn't limit you to going through one company.
Almost every other response was something about MS being evil, MS wants to make money off this (so shame on them), MS is reinventing the wheel, MS is so stupid they don't even know that color shifting in print will screw their scheme, MS will never be able to maintain uptime on their service, etc. etc. etc.
What did you expect from Slashdot?
My issue with it is the reinventing the wheel in such a way that you have to go through them. A more versatile version of the wheel already exists and is already an ISO standard. I don't see how this adds any value, but see how it adds a number of limitations for no good technical reason.