The (upside or downside, depending on your view) to this is a lot of stores are looking to provide an omni-channel experience - install a store's app on your mo

The (upside or downside, depending on your view) to this is a lot of stores are looking to provide an omni-channel experience - install a store's app on your mobile and login with your web login/loyalty card #/etc. The app can send your MAC address along with your login to the store's server. When you walk into the store.. as long as wifi on your mobile is turned on (association not necessary), access points in the store can see your mobile phone's wifi beacons and do a lot of things: send you a push notification, send the store manager a push notification, track your path through the store for targeted advertising, etc.