With the Internet, simple ideas steadfastly executed work best, such as Google's link-powered search engine, Facebook's hive of connected friends, and Twitter's tiny message broadcasting system. The same goes for AWS (Amazon Web Services): Anyone can upload virtual machines, store data, and run compute jobs in the cloud just by filling in a few Web forms.

Last week's re:Invent conference was a reminder of how far AWS's simple idea has come. AWS, the provider that defined cloud computing, has built up a vast ecosystem of partners and keeps piling on features to broaden its appeal, with even conventional enterprises now thinking about moving production workloads to its cloud.

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That proposition would have been hilarious just a few years ago. From the outset, AWS got hammered by traditional IT. You're going to let anyone in the company with a credit card do what? Have you considered the security risks? What about quality of service? Go ahead, play with it for dev and test purposes if you must, but for god's sake don't put anything serious up there.

Conservatism of this type left an opening for other cloud providers such as Rackspace and SoftLayer, whose roots in hosting and managed services enabled them to peddle offerings that suited enterprise IT better. In a recent interview, SoftLayer CEO Lance Crosby told me that part of his company's mission was to give complete control to enterprise customers, right down to the driver level on dedicated hardware. In fact, most newer IaaS players, including HP and Verizon, talk about striving to meet the specific configuration demands of enterprise customers. Of course they play up AWS's outages and reports of inconsistent performance.

Meanwhile, a funny thing has happened to the way enterprises procure technology. With or without the blessing of IT, departmental and line-of-business managers are increasingly going direct to providers for SaaS apps or IaaS offerings. No doubt you've heard Gartner's pronouncement that the CFO will spend as much on technology as the CIO by 2017. A lot of that investment will go to customer-facing "systems of engagement," mainly relating to e-commerce, that need cloud infrastructure from the likes of AWS to scale properly and meet the highly variable demands of public Web and mobile apps.