This sounds like a scene from the movie Minority Report starring Tom Cruise. Unfortunately, it is fact, not fiction.
Facebook has begun a roll-out of Place Tips – a system allowing businesses to send updates to a person’s smartphone when they are nearby. Once a business, such as a coffee shop or restaurant or store, sets up a beacon, the device can detect when a Facebook user is within a set distance. The beacon can then send “fun, useful and relevant” information into the user’s News Feed.
According to Facebook’s explanation page, this information could include content posted by friends in the same place, as well as popular menu items and upcoming events. Of course, targeted advertising aimed at the Facebook user’s interests will also be shown.
The Facebook beacons are available free of charge to any business that wishes to provide targeted advertising to its customers.
You can read the chilling details on Facebook’s web site at https://www.facebook.com/business/news/place-tips-for-businesses.
This is another reason why I will not install Facebook software on any device I own.