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Facebook rolls out location sharing

Feature will alert when someone you know is near

Andrea Vaccari’s location was shown in a Facebook smartphone demonstration.

Associated Press

Andrea Vaccari’s location was shown in a Facebook smartphone demonstration.

NEW YORK — US Facebook users will soon be able to see which of their friends are nearby using a new feature the company is launching on Thursday.

The ‘‘Nearby Friends’’ feature must be turned on by the user, so people should not expect to broadcast their location unknowingly. It will use your smartphone’s GPS system to tell your Facebook friends you are nearby — provided they have the feature turned on as well. Rather than share your exact location, it will show only that you are nearby, say, within half a mile.

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If you like, you can manually share a more precise location with a specific friend you would like to meet up with. Friends can see where you are in a particular park, airport, or city block. By default, your exact location will be shared for only an hour, although you can change this.

Nearby Friends launches amid the growing popularity of location-based mobile dating apps such as Tinder and Hinge. But unlike those apps, Facebook’s feature will let you meet up only with people who are already your friends.

Facebook, whose motto has long been ‘‘move fast and break things,’’ built a lot of precautions in this new tool as it tries to avoid privacy fiascos that often bubble up when it makes changes to its service.

The new motto, ‘‘ship love,’’ is evident in the cautious rollout of Nearby Friends, said Jules Polonetsky, director of the Future of Privacy Forum, an industry-backed think tank in Washington. He has advised Facebook on privacy issues, including the latest feature.

He believes Facebook is showing ‘‘a deeper appreciation that with a billion users, any change needs to be implemented in a way that doesn’t surprise the audience.’’ That’s especially so when it comes to privacy, especially when it comes to location sharing.

‘‘Once you start bringing this to a mass audience, you need to be cautious,’’ Polonetsky said, ‘‘so inadvertent oversharing is not possible.’’

Nearby Friends also will not be available to users under 18, said Andrea Vaccari, a product manager at Facebook. He said the tool ‘‘makes it easy to join your friends in the real world.’’

Of course, all the safeguards and slow rollout mean that most users will not have the feature available right away on Thursday but rather in the coming weeks and months. Initially it will go to people who are likely to appreciate it, Vaccari said, such as people who have ‘‘checked in’’ to various restaurants, bars, or other locations using Facebook.

Unlike with other features, Facebook is not forcing people to use Nearby Friends. Therefore, there is a possibility it will not catch on widely.

But Vaccari is optimistic.

Vaccari joined Facebook in 2012, when the company acquired Glancee, his startup service for meeting nearby people who have friends and interests in common. He has been working on the new feature since then.

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