The social media giant does so by monitoring where users have been using its location tracking.
“Driving foot traffic to store locations remains a priority for marketers, and many businesses are doing this with our store visits objective,” said Facebook. “Facebook store visits reporting is an estimated metric based on information from people with location services enabled on their phone.
“Now, thousands of businesses across more than a dozen countries are eligible to use Facebook's store visits reporting to understand the impact of their ads on foot traffic to their stores.
“Select businesses that are eligible for store visits reporting can now also create custom audiences made up of people who have recently visited their store. This feature allows businesses to re-engage in-store audiences with more relevant and compelling campaigns, as well as create lookalike audiences.
“For example, an apparel brand may use these custom audiences to show an ad with their new winter arrivals to people who have visited their locations. They can also choose to exclude in-store customers, for example, when running a promotion available only for new customers.”
Facebook’s location tracking can be switched off. Just go to “Settings” and then to Adverts section where you can manage your preferences.