Retail stores are tracking users movements through their cell phones

This is the latest, "It's spooky, but is it wrong?" privacy story.

Stores listen for customers' cell phones as they probe for WiFi hot-spots, then use that information to observe foot traffic in the store. Perhaps the data is anonymized, but consumers, I'm sure, won't be comfortable with it. Earlier this year, Nordstrom ended an in-store cell phone tracking trial after negative consumer reaction, for example.

Last month, Sen. Chuck Schumer (D-N.Y.) announced an industry agreement, with location tracking firms voluntarily agreeing to a code of conduct. It includes conspicuous signage and the opportunity to opt out.

Here, I discuss the new technology with NBC's Chris Clackum.