In a separate study, Forrester Research found that the proportion of marketers using mobile has stagnated at less than one-third. Worse, only 21% say they plan to add mobile to their marketing mix in the next year, compared to 36% a year ago. About half of the agencies polled by the MMA characterized mobile marketing as "experimental," and most described campaign results as "average."

Both Forrester and the MMA predict strong growth for mobile ad spending this year, despite the wider pullback. But growth rates for emerging categories often seem gaudy compared to established categories since they are starting from much smaller bases.

At the MMA's Mobile Marketing Forum in New York last week, panelist Brian Quinton, executive editor of Chief Marketer, said he was not especially surprised by the study findings. "I think a lot of people are still in the learning process with mobile," he said. Nothing new there. What momentum there is around mobile media and advertising is being driven by devices -- the iPhone and a growing field of smartphone rivals.

That's a lot different than the Internet or television. Imagine Facebook or "House" depending on what type of PC or TV set someone was using for their success. But until smartphone technology becomes more ubiquitous across the wider mobile population -- akin to the shift from dial-up to broadband Web access -- the best devices will call the tune (or iTunes) in the wireless realm.

If, as rumored, Apple lowers the price on the new iPhone, from $199 to $149 or $99, that would mark another step toward turning the smartphone into a mass media platform.

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