Forget Microsoft vs. Google. This Decade, It's an Apple-Google Slugfest.

Google's new "superphone," the Nexus One, stole all the headlines yesterday, but there was another bit of tech news worth trumpeting: Apple's reported $275 million purchase of Quattro Wireless, a mobile advertising platform.

True, mobile advertising isn't as sexy as a sleek new gadget. But the Quattro purchase highlighted the fact that there are really only two tech companies worth caring about anymore, and the lines between them are growing blurry. It used to be that Apple made the hardware and the gorgeous desktop software, while Google kept its head in the cloud, focusing on Web-based applications and, of course, advertising. But over the past year, Google has stepped on Apple's toes—hard. The Android operating system, a rival app store, Google Voice, and now the Nexus One are the first volleys against Apple's dominance in the smart-phone market.

Now Steve Jobs is lacing up his Doc Martens and getting ready to stomp right back. Apple's purchase of Quattro is the Cupertino company's first foray into advertising, and a signal that it's not going to cede the mobile ad market to the nerds over in Mountain View. Google has a head start—in November it bought AdMob, a larger, better-known mobile advertiser—but Apple has privileged access to the thousands of programmers who have already built apps for the iPhone, which house much of the real estate for AdMob's and Quattro's ads.

It'll be a slugfest—and Microsoft will be on the sidelines, watching pathetically. Windows is still a cash cow, and Microsoft will probably always dominate the market for desktop operating systems and office productivity suites. But it's looking likelier that, five years from now, when we connect to the Web, we'll generally do so from a smart phone, netbook, or tabletlike device. Microsoft does build operating systems and software for some of those markets, but none that anybody is excited about. In other words, forget Bing, and forget the Microsoft-vs.-Google bout. Those are distractions, or at best opening matches to warm up the crowd. The headlining event of the next decade is the bout between Apple and Google.