Does anyone else not feel so good about a future of computing where everything but the application layer is rented from Jeff Bezos?
Nowadays? If Twitter launched today they would have had no trouble scaling up from one user to a hundred million within weeks. AWS is a major (MAJOR) factor in the startup boom, and allows for crazy levels of scaling for new startups that attract a lot of users. If you set up your stuff right before launch, getting slashdotted (or the HN variant) is a thing of the past. The only limit to scaling now is your credit limit.
Disclaimer: Views expressed are my own and do not reflect any positions held by my employer.
The significance is where the line of abstraction is drawn, as has been the case every time programming moves up an abstraction layer.