Why is Amazon so big in the Cloud, aren't they just a retailer?

Episode 1547 (1:29:32)

Scott from Orange County, CA
Amazon

Scott went to the recent ReInvent convention for Amazon services and he learned a lot about the power of data in the cloud. Leo says that Amazon is the clear leader in cloud based web services, trouncing Google and Microsoft. And the irony is, it was largely an afterthought to their retail business. Leo now thinks that Amazon's goal is to get a fraction of every financial transaction on the planet. Even a penny would amount to trillions of dollars.