By a _lot_ of people, though, you undoubtedly mean the 1% of Windows users who actually use [[ insert OSS filesystem here]]. MS gets _nothing_ for doing this other than the goodwill of OSS people who will likely never buy Windows anyways. I have a feeling that it's not that MS doesn't want to be interoperable, but rather that they don't foresee any ROI via ext3.

No costs other than human labor to set it up and distribute CD keys would sit on top of that - Amazon S3 can serve the file directly to the customer. There are also numerous other file delivery providers that are even less expensive. They don't have to use Akamai for everything!

Or they could pay USD $0.17 per GB using Amazon S3 http://aws.amazon.com/s3/#pricing