There have been many attempts at proximity marketing over time, initially by sending information as contacts over Bluetooth to mobile phones.
Nowadays much more suited technologies for this are beacons and geofencing, where it is easier to discriminate what information customers will interact with, provided mobile apps for the purpose provide such screening and granularity.
The following article talks specifically about Google’s way of handling beacons. Not the least it’s interesting in terms of the use cases it mentions.
CliqTags has support for iBeacons (and geofencing) via CliqTags Spotter (using Apple iBeacon) or Google Eddystone-URL via Google Nearby.
For more about how CliqTags supports beacons, see: