A technology becomes truly disruptive when it drives the marginal cost of something that used to be scarce and expensive to approach zero. Thus, it used to be to deploy software at scale, you had to fund a data center, buy a set of servers, storage, and networking gear, build an in-house IT management capability, and buy an expensive stack of enabling software before you could even get started. Now you can get all that from Amazon or Microsoft on a pay-as-you-grow model.