"It's important to remember that steel coil  DOES NOT share information that identifies customers personally outside of Verizon," Verizon said. On its website, AT&T said, "Your personal information will not be used outside of the AT&T Alerts program." And its terms of use point to the company's , which says.

"Verizon Selects analyzes this information about customers to see whether they fit into certain audiences Verizon or third party marketers are trying to reach," Neptune said. "Depending on the results, participating customers will receive marketing messages or offers that may be of more interest to them than what they see or receive today." AT&T said its program, called , will use "geo-location technology" to offer customers "discounts, rewards and offers via text message when they are near participating retailers and brands," including Gap, Staples and Zales. gives this example: "If you're approaching a Gap, for example, AT&T ships you  text message out of the blue with a link to a coupon for jeans."

"We do not provide Personal Information to non-AT&T companies for the marketing of their own products and services without your consent." But privacy groups say such programs are deceptive and potentially illegal. "Users' location data, web browsing histories, internet search terms, demographic information, and mobile device usage information are often personally identifiable," in an October 2011 complaint with the Federal Trade Commission regarding Verizon's business practices. "Verizon Wireless's collection and disclosure of this personal information violates user expectations, diminishes user privacy, and contradicts Verizon Wireless's own representations," EPIC said in the complaint.

Both AT&T and Verizon say the programs will work on an opt-in basis — only customers who choose to participate will do so. And they emphasize that they won't share personal information with other companies.

Verizon said it will offer the program to some of its customers, in what GigaOM described as a pilot program, while AT&T has a . Verizon targets businesses with a program called Precision Market Insights, which Verizon says can use collected data to boost their sales.