eMarketer forecasts that the number of U.S. consumers who watch TV on mobile phones will reach 15.0 million in 2009, up from 1.2 million this year and an estimated 3.0 million in 2006. Major media, telecommunications and entertainment companies are betting on mobile content, thus providing a new platform for marketers. "Just as online video advertising has taken off because of the way it blends video's high brand engagement with the Internet's interactive, tracking and targeting capabilities, so too will…mobile video advertising," says Debra Aho Williamson, author of eMarketer's new report, "Mobile Entertainment: The Rise of the Very Small Screen."

According to M:Metrics data from October, however, fewer than 10 percent of U.S. mobile subscribers had used their phone's browser to get news and information, send a photo message or purchase a ringtone. Fewer than 5 percent had purchased wallpaper or a screen saver or downloaded a mobile game.

And according to an A.T. Kearney survey, two-thirds of U.S. respondents said they would likely use their mobile phones only to make and receive calls. However, about one-third of those age 13-34 surveyed by the Management Network Group were interested in phone applications such as commercial-free radio and mobile TV.