This could get creepy fast…. There are plenty of scenarios in which Facebook casually connecting you with people because your phones were in the same place at the same time could end disastrously. Imagine going to an Alcoholics Anonymous meeting, and then getting “Friend” suggestions the next day for members of the group along with their full names and profile information. Or getting hit on at the bar by a guy that gives you the creeps, giving him the cold shoulder and no information about yourself, but later getting a ‘Friend Request’ from him. Or visiting an abortion clinic and discovering that one of the abortion protestors outside was offered up your identity by Facebook.
This is very dangerous and people need to let FaceBook know they are not cool with this. And I’m sure the NSA will love this data as well.
UPDATE: After the story broke, FaceBook now says they no longer use location data to recommend friends. Hmmm, hopefully nobody got injured, or worse, while they were.