Geofencing is used for a variety of applications, but it is commonly used in direct to consumer marketing. When customers and their mobile devices enter a defined geographic area (e.g., within a specified range of a store location), they are shown a marketing message, such as a discount or coupon, to encourage them to visit the sponsoring business. Now, geofencing has entered the political arena, with campaigns using it to identify people who attend candidate rallies or visit locations that identify them as potential supporters of a candidate.
According to the Wall Street Journal, “Armed with this data, campaigns can track down and segment potential voters based on apps they use and places they have been, including rallies, churches and gun clubs. In some cases, voters might see an ad on their mobile phone. In others, companies can match data to a specific person, allowing campaigns to determine who gets a fundraising call or a knock on the door.”
Many smartphone apps broadcast their location to online data brokers and advertising companies. Apps generally ask for permission to access and send user information, but anyone who wants to use the app must agree to the terms. Terms that many users never read. Apps may say they gather location data to target advertising, but often do not disclose that the data may be used for political purposes. In the European Union, privacy laws forbid collection of certain sensitive data, such as that relating to religion, health or politics, without explicit consent.
Over time, your location data can reveal where you live and work. It can also reveal when you go to the gym, which doctor you go to, how often you attend religious services and other associations.
It is possible to limit location tracking by telling your smartphone to periodically reset the “advertising ID” and by turning off location access or setting it to track only when the app is in use. For specific instructions for iOS and Android smartphones, see this article on LifeHacker.
