Something happened in the first years of the 20th century that would have seemed unthinkable just a few decades earlier: Manufacturers began to shut down and dismantle their water wheels, steam engines and electric generators. Since the beginning of the Industrial Age, power generation had been a seemingly intrinsic part of doing business, and mills and factories had had no choice but to maintain private power plants to run their machinery. As the new century dawned, however, an alternative started to emerge. Dozens of fledgling electricity producers began to erect central generating stations and use a network of wires to distribute their power to distant customers. Manufacturers no longer had to run their own dynamos; they could simply buy the electricity they needed, as needed, from the new suppliers. Power generation was being transformed from a corporate function to a utility.

Almost exactly a century later, history is repeating itself. The most important commercial development of the last 50 years — information technology — is undergoing a similar transformation. It, too, is beginning an inexorable shift from being an asset that companies own in the form of computers, software and myriad related components to being a service that they purchase from utility providers. Few in the business world have contemplated the full magnitude of this change or its far-reaching consequences. To date, popular discussions of utility computing have rarely progressed beyond a recitation of IT vendors’ marketing slogans, laden with opaque terms like “autonomic systems,” “server virtualization” and “service-oriented architecture.”1 Rather than illuminate the future, such gobbledygook has only obscured it.

The prevailing rhetoric is, moreover, too conservative. It assumes that the existing model of IT supply and use will endure, as will the corporate data center that lies at its core. But that view is perilously shortsighted. The traditional model’s economic foundation already is crumbling and is unlikely to survive in the long run. As the earlier transformation of electricity supply suggests, IT’s shift from a fragmented capital asset to a centralized utility service will be momentous. It will overturn strategic and operating assumptions, alter industrial economics, upset markets and pose daunting challenges to every user and vendor. The history of the commercial application of information technology has been characterized by astounding leaps, but nothing that has come before — not even the introduction of the personal computer or the opening of the Internet — will match the upheaval that lies just