Smart Phone Spying

The millions of people who use their cellphones daily to play games, download applications and browse the Web may not realize that they have an unseen companion: advertisers that can track their interests, their habits and even their location.

Eswar Priyadarshan, the chief technology officer of Quattro Wireless, which places advertising for clients like Sony on mobile sites, says he typically has 20 pieces of information about a customer who has visited a site or played with an application in his network.

An advertising system could know, for instance, that someone is 27 years old, male, a New England Patriots fan (which NFL.com can track), plays Blackjack, travels frequently between Boston and New York on weekdays (which applications using GPS can track) and uses a 3G iPhone. That would make him attractive to a host of advertisers, like the Delta Shuttle or a Las Vegas hotel, whose ads would appear while the consumer was browsing the Web on his phone.

"It's potentially a portable, personal spy," said Jeff Chester, the executive director of the Center for Digital Democracy, who will appear before Federal Trade Commission staff members this month to brief them on privacy and mobile marketing.

Several firms are experimenting with a program called AisleCaster that can offer specials based on a person's exact location in a supermarket aisle or mall.