Sprint and other mobile companies plan to provide customized ad buys that will deliver very specific demographic, geographic or psychographic groups - and that has raised some privacy concerns, reports AdAge.

About a dozen marketers, including the U.S. Navy, AOL and Major League Baseball, have signed up to experiment with Sprint Nextel's offer of ad placement on its "deck," the landing page for accessing the internet from cell phones which lists websites that people can click to, a place carriers never considered selling a few years ago, but competition has forced them to reassess.

According to Sprint's John Styers, general manager-mobile advertising, each campaign is being sold based on number of impressions, in a traditional cost-per-thousand model; he is quoted as saying each campaign is "unique" - but that "$100-plus" is what the industry is talking about for pre- and post-roll mobile video ads.

Marc Lefar, chief marketing officer at Cingular Wireless, cautioned, "you have to be very careful about privacy issues. The question becomes: What will customers be willing to accept and what do they need to receive in terms of value to accept them?"

Some research backs Lefar's concerns. Fareena Sultan, assistant professor of marketing at Northeastern University, Boston, said her studies have found privacy is "huge and top-of-mind" with cell phone users, particularly women and the over-30 crowd. "The brand has to become an advocate for the consumer," she said.