Facebook has tested, but does not use, location data to recommend Friends
In 2016, Facebook gave conflicting accounts of whether the service uses location data in order to recommend prospective Friends in its "People You May Know" feature. When the company first admitted - for publication - that location data was indeed one of the signals it used, many users felt this explained some of the PYMK recommendations they were seeing and experts pointed out the similarity to the NSA's techniques as were exposed in 2013 by the Snowden revelations. A few days later, however, the company recanted and said it does not use location data for this purpose, though it had run a brief test late in 2015 that temporarily used it. However, it's clear that Facebook does use smartphone location for other purposes, such as tracking which stores users visit and geotargeting ads. Understanding how PYMK works is difficult because the company considers the methods it uses to make these recommendations proprietary information.
Writer: Kashmir Hill
Publication: Splinter News