According to the official announcement, the feature is meant to be a way to find out when friends are in the nearby area, so you can hang out face-to-face. Though the social networking site has gotten a reputation for distancing people in their social interactions, they have always insisted that Facebook is a tool to enhance, not limit, relationships.
If you turn on Nearby Friends, you’ll occasionally be notified when friends are nearby, they explained on their official newsroom page.
So you can get in touch with them and meet up. For example, when you’re headed to the movies, Nearby Friends will let you know if friends are nearby so you can see the movie together or meet up afterward.
If, like me, you are creeped out by the idea of people knowing where you are, as much as by precise location, whom you haven’t explicitly told, you can turn the feature off.
You can also set specific parameters. For example, you can share with certain friends, or for a certain duration of time. Or see when friends are ‘on the move’, if they have given you access.
This is a weird feature. While Facebook makes it seem like this incredible ability to see where friends are so they can join you, that is so unnecessary. Who tracks a friend and then shows up at that location as a result of their tracking? This is like friendship-by-stalking.
Here is a thought: if you want to meet up with someone, call them and say, “Hey, wanna meet up?” From there, you can work out all the details you need, GPS not required.
What if someone manages to get into your account, and turns on the feature without you noticing? I can think of at least a dozen relatives on my own list who don’t even understand that private messages and wall messages are not the same thing. Letting them loose with an optional tool that helps you to track them at all times seems a little bit reckless.
Source: Facebook Newsroom