i do so with a man from brickstream, the manufacturer of the prubilioduct. it watches whether we walk in as a group, and our heights. >> how many people come into the store and how many converts into sale. in other words, where do people go and stop and dwell. >> another advantage is that information gathered can drim the time customers wait online to check out. the smart device tracks shoppers via smartphones. retailers record their sell phone ids, store it and monitor it as they shop. to avoid being foloed by phone a customer has to opt out. >> for the retailers to help themselves, it will leave a bad taste in the consumer's mind. >> they must post signs in stores alerting shoppers that they are being tracked and providing instructions on thou opt out. privacy advocates say these measures are a first step in coping with this technology. >> in the fib and google age shoppers may adapt to leaving a footprint behind. >> big brother is out there. we have come to terms with that and it's going to get bigger. >> season's greatings. president obama's message to a