The geo thing is really happening.

I also have the theory that they are using WiFi names / AP MAC addresses as well. If you happen to be connected to the same private WiFi network, you probably know each other.

Facebook has a patent for using dust and scratches on photos to track which camera they came from. But they claime(d) not to be using WiFi or Geolocation for the PYMK feature - https://gizmodo.com/facebook-knows-how-to-track-you-using-th...

Based on the track record of other Facebook claims of the "we don't do X" type, this is basically proof that they do and/or did do both of these things. Maybe "accidentially" and "unintentionally" ;-)

Which is one big reason why the only sensible way to use Facebook on mobile is to delete the app and use only a browser, while keeping your location sensors turned off.

There is a nice app called Frost that is basically a wrapper around the web interface with convenience features, and is free (i.e., available on F-Droid).

As one of the factors probably, but they don't recommend random people who are nearby. There has to be some actual connection (friend-of-friend, address book, in the same group etc.)

> but they don't recommend random people who are nearby

I think that's probably true. You need to spend sufficient time near someone--like within a few feet or so.

I had an interesting experience where Facebook recommended me as a friend to someone I sat next to on an airplane, with whom I had a conversation with. My phone was in airplane mode. Not sure how that happened, TBH!

They probably looked you up afterwards on Facebook or another site using Facebook analytics.

It could be based on connecting to the same in-flight WiFi.

And you might be able to correlate seating with WiFi strength? :)

so a stalker will get recommended to a 'stalkee' ?

I mean, part of the use case there is that the 'stalkee' will at least be notified that the person s/he has seen four or five times is definitely stalking them. So that's good, I guess.

This post is obviously sarcasm.

Happened to me a few times, some people I randomly met in a bar where recommended to me the next day, super creepy.

Could not be because they checked you out by name on facebook?

Possible, although I've only given them my first name. And this is not just on one occasions, it has happened multiple times. My best guess has always been that Facebook uses some geo targeting to see who was at the same location at the same time.