Young woman clothes shopping (© Image Source-Getty Images)
Updated May 12, 10:25 pm ET
OK, stores, here's the deal: If you really want consumers to support sales taxes for online merchants and stop using you as glorified showrooms, maybe you should stop using their smartphones' Wi-Fi signals to track their every step.

Just a suggestion.

Without their knowledge, the 40% to 70% of all shoppers who have stepped into Nordstrom (JWN) and other outlets with their smartphones on have been tracked by a company called Euclid Analytics through their phones' Wi-Fi requests. Euclid then uses that data to determine specific departments a shopper visits and how long a shopper spends in each department.

Nordstrom told a CBS (CBS) affiliate in Dallas that such information gives it "a better sense of customer foot traffic," but it has since announced it is ceasing its use of Euclid's tracking system. The New York Times speculates that retailers could use that data to shift high-end and downmarket items around their stores based on who walks by them. A Home Depot (HD) spokesman said that while that retailer once tested Euclid's tracking product a handful of its stores, it no longer uses it.

Shoppers looking to go untracked have to turn off their Wi-Fi or turn off their phones completely. If those consumers want to opt out, they have to go to a Euclid site -- whose existence they may not be aware of -- and tell Euclid they want out of the service they weren't asked to participate in.

The good news is that, once users opt out, their information is wiped from Euclid's database along with all of their phones' records. The bad news is users not only have to dig around for their phone's "MAC address," the code that identifies their device to a network, but they have to provide that code to Euclid to get scrubbed from its files.

Although Euclid is tracking 50 million devices in 4,000 locations, it assures shoppers that it doesn't cull data about "who you are, whom you call or the websites you visit." Shoppers' anonymous data is bundled with data from other individuals, resulting in an aggregate report of anonymous information.

Still, if customers want to be tracked and have their spending habits used for marketing purposes, they can just shop online.

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