New system tracks mall shoppers using cellphone signals.

The Footpath technology uses monitoring units distributed throughout malls to track customers behavior by triangulating their cellphone signals. Reports are compiled on where customers spend the most time in the mall, to help retailers decide where to place advertising. It will even show if a customer has gone to a specific shop after seeing a certain sign or billboard.

The technology has been trialed in two US malls, with the malls quick to assure customers that no personal data is collected or stored.

Potentially a further privacy concern for customers would be if the technology was combined with security camera data. Facial recognition technology could be used to cross reference against payment data to build large profiles of individual shoppers behavior.