I like that Amazon is sharing the benefits of their massive scale with their customers. Though, by keeping their margins slim, they'll make it increasingly harder for smaller vendors to compete.
"If you have bigger lungs than your competitor, all things being equal, force them to compete in a contest where oxygen is the crucial limiter. If your opponent can't swim, you make them compete in water. If they dislike the cold, set the contest in the winter, on a tundra. You can romanticize all of this by quoting Sun Tzu, but it's just common sense."
I think BitCasa offers unlimited storage. They had stated some time ago that they can offer unlimited storage because their algorithms for content matching were very effective at limiting what they actually had to store. Size becomes a competitive advantage.