Facebook offers to share people's location

Facebook is unveiling a new service to let users know when a friend is close by.

The company said it had consulted with privacy advocates in government ahead of Thursday's launch, but the service nonetheless invites criticism from privacy advocates who have worried about the amount of information the social network captures about its users.

People will have to opt in to the new Nearby Friends feature, and Facebook is forcing users to affirmatively choose if they want to share details about their movements. Nothing will change for users who don’t assertively turn it on, Facebook said.

Jules Polonetsky, executive director of the Future of Privacy Forum, said that developers seemed aware of the scrutiny the project would draw and “were appropriately cautious" about privacy concerns.

“Most proximity and location apps share precise location and are always on, but Facebook's new service only shares very general location and by default turns itself off,” he said in an email. “And users have to clearly activate the feature and click through a few screens to turn on proximity sharing with specific friends.”

Users who turn the feature on will be able to decide which of their friends will be able to see their general location. The service needs consent from both sides, so both people need to choose to share their location with each other before either of them can see anything.

The program will say whether a friend is within a half-mile or so, but friends farther away will only be located by the city they are in. Users will also occasionally be notified if a friend is nearby in an unusual place, a service meant to connect two people unknowingly on vacation in the same spot, not co-workers who sit next to each other every day. 

Both parties can send a message and, if either of them chooses to, share more specific information about their location, which Facebook suggested would be useful for meeting up in a crowded mall or airport.

“When you share your precise location, the friend you choose will see exactly where you are on a map, which helps you find each other,” product manager Andrea Vaccari said in a blog post. “Then you can meet up and spend time together.”

Peoples' location information will be logged, but only the user will be able to see that record. Users will be able to delete that log permanently.  

The final product, which took two years to develop, will start with a limited rollout, and is only being offered to U.S. users for the time being. 

--This report was updated at 2:49 p.m.