updated 03:27 pm EDT, Thu April 17, 2014
Feature deploying slowly
Facebook has announced an upcoming feature for its iOS and Android apps, Nearby Friends. The function will notify users when friends are within a certain radius, giving a chance to meet up. For security purposes the feature will be off by default, only work if both parties have it enabled, and allow restricting notifications to specific groups -- close friends, for example, or a custom list.
People will further be able choose to share precise location with individual friends for a specific period of time, much like Apple's Find My Friends. Each share will allow a brief 40-character message. The feature will also let people see where others are traveling, down to the city or neighborhood level.
Facebook says that Nearby Friends should deploy in the US "over the coming weeks."