By David Kirkpatrick

(FORTUNE Magazine) – THINK OF APPLE'S RECENT DECISION to start using Intel chips in its Macs as just one move in the mating dance that continually consumes the computing industry. It's like high school--one week you and your friends are ridiculing a girl, and the next week you're going steady with her. Intel, like a glowing but social-climbing prom queen, sees Apple as a partner that can help it stay powerful and move into even classier circles over time. And though Apple has derided Intel's technology for decades, it finally had no choice but to embrace it.

For Intel, this deal means a lot more than gaining a relatively small new customer. (With Apple's global PC market share at 1.9%, its annual business is equivalent to about five weeks of Intel's shipments to Dell.) In important ways the move positions Intel for the future. That's why it spent eight years courting Apple. Executives several times thought they had a deal with Apple's mercurial CEO, Steve Jobs, only to find themselves disappointed.

But Intel persisted, in part because Apple may help it tackle a big strategic challenge. Intel currently lacks a substantial position in any of three critical and fast-growing tech categories, all of them consumer-related: game boxes, cellphones, and portable devices like Apple's iPod. Consumer computing--not the world of business tech that Intel dominates--has become the locus of tech innovation. And Jobs has shown himself capable of figuring out how to stay at the cutting edge of consumer taste; Apple is building must-have devices. With Jobs as partner, Intel should be better able to compete with Microsoft and Sony, who each want their upcoming IBM-powered game boxes to be the main media device for the home.

For its part, Apple needed Intel because IBM, which makes its current processors, couldn't supply chips for notebook PCs, the industry's fastest-growing category. IBM had no intention of spending vast amounts to make its chips work in the low-power versions necessary for notebooks. That's because Apple is its only PC customer and just doesn't buy enough chips to make IBM's investment worthwhile. (Apple's current notebooks use an older chip made by Freescale Semiconductor, formerly Motorola's chip group.) Intel, by contrast, sells processors to scores of PC makers, and invested hundreds of millions of dollars in its Centrino chips for notebooks. Intel has an aggressive roadmap for its full line of chips, and Apple may now employ any of them.

More intriguing is where this new partnership could lead in the long term. Once the Mac OS X operating system works on standard Intel chips, it's just possible Jobs will license it for use on PCs from any manufacturer. (Several PC makers have told FORTUNE they'd love to license the Mac OS.) So far, Jobs says he won't, but the opportunity may get too good to pass up: Later this year Intel plans to begin building into its chips a technology called "virtualization" that will enable two or more operating systems to run on the same PC--OS X and Windows, for instance. And if Jobs were to bite, that would be good for Intel. It hates to be too tied to any one partner like, for example, Microsoft. A more vibrant Apple would help this prom queen divide and conquer.

-- David Kirkpatrick