A mobile Facebook feature called Find Friends Nearby, is coming out of development. Previously this feature was code-named Friendshake.
It will soon be on its way to iOS or Android smartphones. Perhaps springing from the Facebook’s acquisition of ambient social app Glancee, it is still fairly primitive, merely navigating to a browser page on your device.
Here, it will show you a list of other users within a given, undisclosed radius. Presumably, the benefit is to let you quickly add someone in your purview like Find my Friends. It would be interesting to see what privacy settings are on offer.