First Nicholas Carr dropped a bombshell of a book, Does IT Matter? Information Technology and the Corrosion of Competitive Advantage, which argued that corporate IT is increasingly becoming a commodity. Now he's back with a provocative new tome, The Big Switch: Rewiring the World, From Edison to Google (W. W. Norton, 2008), wherein he makes the case that IT as we know it may disappear completely.

The idea is that computing in the age of the Internet is well on its way to becoming a utility, much as the electricity grid changed power distribution more than a century ago. Carr, a former executive editor at the Harvard Business Review and a pot-stirring blogger at RoughType.com, mixes history, reportage and a dash of futurism to create a persuasive vision that CIOs may find unsettling—but cannot afford to ignore.

An excerpt of the book follows.

The network—the Internet, that is—has become, literally, our computer. The different components that used to be isolated in the closed box of the PC—the hard drive for storing information, the microchip for processing information, the applications for manipulating information—can now be dispersed throughout the world, integrated through the Internet and shared by everyone. The World Wide Web has truly turned into the World Wide Computer.

Computing, as we experience it today, no longer takes a fixed, concrete form. It occurs in the Internet's ever-shifting "cloud" of data, software and devices. Our personal computer, not to mention our Blackberry, our mobile phone, our gaming console and any other networked gadget we use, is just another molecule of the cloud, another node in the vast computing network. Fulfilling Napster's promise, our PCs have merged with all the other devices on the Internet. That gives each of us using the World Wide Computer enormous flexibility in tailoring its workings to our particular needs. We can vary the mix of components—those supplied by utilities and those supplied locally—according to the task we want to accomplish.

To put it another way, the World Wide Computer, like any other electronic computer, is programmable. Anyone can write instructions to customize how it works.

As the capacity of the World Wide Computer expands, it will continue to displace private systems as the preferred platform for computing. Businesses will gain new flexibility in assembling computing services to perform custom information-processing jobs. Able to easily program the World Wide Computer in their own ways, they'll no longer be constrained by the limits of their own data centers or the dictates of a few big IT vendors.

Because of computing's modularity, companies will have a wealth of options as they make the leap to the utility age. They'll be able to continue to fulfill some of their computing requirements through their in-house data centers and IT departments while relying on outside utilities to satisfy other needs. And they'll be able to continually fine-tune the mix as the capabilities of the utilities advance.

In contrast to the switch-over to electric utilities, buyers don't face an all-or-nothing choice when it comes to computing. While smaller companies have strong economic incentives to embrace the full utility model quickly, larger companies will need to carefully balance their past investments in in-house computing with the benefits provided by utilities. They can be expected to pursue a hybrid approach for many years, supplying some hardware and software requirements themselves and purchasing others over the grid. One of the key challenges for IT departments lies in making the right decisions about what to hold onto and what to let go.

In the long run, the IT department is unlikely to survive, at least in its familiar form. It will have little left to do once the bulk of business computing shifts out of private data centers and into "the cloud." Business units and even individual employees will be able to control the processing of information directly, without the need for legions of technical specialists.

Excerpted from The Big Switch: Rewiring the World, From Edison to Google. Copyright January 2008 Nicholas Carr, W. W. Norton, all rights reserved.