Attention shoppers: There’s a new aisle open in the privacy debate. Supermarkets are cheering a new way to discourage "basket splitters"?pesky shoppers who don’t put all their food purchases in one store’s basket?while privacy advocates are booing about Big Brother watching what you eat.

Suppose Martha Shopper has a membership card from Stop & Shop. She likes the discounts and coupons, but not the way the supermarket chain knows how many tubs o’ lard she buys each month and how few bunches o’ broccoli. What she may not know is that if she (or anyone else) visits SmartMouth.com and punches in her card number, up comes her buying history, along with analysis and tips for improving her diet.

Stop & Shop, which has 275 stores in the Northeast, partnered with the Watertown, Mass.-based SmartMouth Technologies to provide the service, but privacy advocates fear that the move could lead to more sinister information-sharing?such as with health-insurance companies. "[The service] plays right into fears that privacy advocates have had [about customer cards] from the outset: one, that your data will be shared without permission, and two, that your data will be used to keep tabs on whether you’re eating healthy or not," says Katherine Albrecht, founder and editor of Consumers Against Supermarket Privacy Invasion and Numbering (CASPIAN).

Officials are quick to say that no identifying information is sent to SmartMouth, and they insist that few customers care. Midway through a six-month pilot program with SmartMouth, Stop & Shop Director of Customer Relationship Marketing Ed Porter reported that only a couple of customers have complained. "We’ve had some inquiries, but thankfully it’s not a big issue," he says. "It’s more some folks realizing, oh, you’re actually collecting information when I use my Stop & Shop card."

Anyone with a Stop & Shop card can access his buying history at SmartMouth.com, but so far the program has only been promoted in Rhode Island and parts of southeastern Massachusetts. Porter said the company will decide in July whether to expand it.

In an odd twist, Albrecht says SmartMouth might actually be good for privacy in the long run. That’s because the more consumers know about the information gathered by CRM systems, the more likely they are to complain?and the harder it gets for stores to ignore those complaints. Visit Albrecht’s site at www.nocards.com.