History of Amazon AWS
www ccc stashed this in Cloud Computing (History)
History of AWS:
So it literally was an expansion of internal infra/services...
They had the courage to build this market from scratch.
Even as a non-dev, I am aware of EC2 and S3 dominance. That's also why I was interested.
It's funny because Google and Microsoft won't get into a market until it has already been proven huge.
Amazon has no such constraint.