iCloud Storage Underestimated
I think the industry is completely underestimating the impact that iCloud and Apple's cloud storage implementation is going to have.
Applications synchronising data between devices is going to just work, without the user having to do anything to set it up. No accounts, no paying for separate services, nothing. Just buy the app in iTunes and the app appears automatically on any compatible devices that the user has. Use the app on one device, and the data you create is immediately accessible on other iOS devices or from Mac apps.
The revolutionary part of this is that it's no work for the user to set up and very little work for the developer (almost no work if you use the right APIs to manage your documents), so it's going to get used. A lot.
Apple's good at solving hard problems in ways that make the solution seem simple.
And because of the commercial ecosystem Apple has created, they can afford to offer a limited (but adequate for many users) amount of iCloud storage for free. That's going to be tough for anyone else.