CBS plans one of the first serious experiments with cellphone advertising that is customized for a person's location. Its CBS Mobile unit is teaming up with the social networking service Loopt, which allows its subscribers to track participating friends and family on their mobile phones.
The ads will appear on two Web sites that are tailored for mobile devices, CBS Mobile News and CBS Mobile Sports.
Using Loopt's G.P.S.-based technology and capitalizing on its relationships with mobile carriers, CBS Mobile wants to make it easier for advertisers to aim promotions at consumers more precisely as they walk by particular stores and restaurants.
“Consumers are savvy enough to expect advertising,” said Angela Steele, a director at Starcom USA, an ad-buying agency based in Chicago. “They are accepting of it, but they want it to be relevant. If they are getting something they are interested in, that is great. But if they are sending ads that are not relevant, people won't want it.”