Google (NASDAQ:GOOG) on Monday announced a new AdWords system, with which advertisers can instantly push pitches originally meant for PCs onto iPhones and Android-enabled handsets such as the popular G1.

Product marketing manager Alexandra Kenin explained in a blog post: "Now, advertisers will be able to display ads exclusively on these mobile devices, create campaigns for them, and get separate performance reporting. If you prefer not to show your desktop ads on these phones, you can opt out and show ads only on desktop and laptop computers."

And vice versa. Ads once intended for the desktop can now follow you everywhere. If that sounds eerily like a Philip K. Dick novel, as if your digital life is about to be consumed by one pitch after another, it isn't.

Not yet, anyway.

Neither Apple (NASDAQ:AAPL) nor AT&T (NYSE:T) nor Deutsche Telekom's (NYSE:DT) T-Mobile are interested in seeing DoubleGoo annoy their customers. Ads will be confined to the browser and, even then, only in searches. Google wants to help you find what you want, and if it gets paid for the effort, so much the better.

But if we're seeing more mobile ads, it's because, factoring in location data, they can be made more relevant. That's the pitch for Loopt, a Baby Breaker that maps your network of friends in real time and ultimately aims to subsist on advertising.

Mobile-ad distributor AdMob -- think Google, but for mobile phones -- offers hope. Executives there recently told VentureBeat writer Matthaus Krzykowski that they had, for the first time, secured "upfronts in the million-dollar range" for 2009. Upfronts are commitments made for planned ad placements.

Both the iPhone 3G and T-Mobile's G1 have built-in GPS systems, as do Nokia's (NYSE:NOK) new N97 and Research In Motion's (NASDAQ:RIMM) BlackBerry Storm. Both platforms should see additional location-based services as a result.

For now, mobile ads remain on the minority report. But that won't last. Nokia, RIM, Samsung ... they're all way too smart to let their smartphone-cum-pitch platforms miss this opportunity.

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Fool contributor Tim Beyers had stock and options positions in Apple and Google and a stock position in Nokia at the time of publication. The Motley Fool's disclosure policy is thumb-shopping for the holidays.