How Facebook Figures Out Everyone You've Ever Met (gizmodo.com)

"I deleted Facebook after it recommended as People You May Know a man who was defense counsel on one of my cases. We had only communicated through my work email, which is not connected to my Facebook, which convinced me Facebook was scanning my work email," an attorney told Gizmodo. Kashmir Hill, a reporter at the news outlet, who recently documented how Facebook figured out a connection between her and a family member she did not know existed, shares several more instances others have reported and explains how Facebook gathers information. She reports: Behind the Facebook profile you've built for yourself is another one, a shadow profile, built from the inboxes and smartphones of other Facebook users. Contact information you've never given the network gets associated with your account, making it easier for Facebook to more completely map your social connections. Because shadow-profile connections happen inside Facebook's algorithmic black box, people can't see how deep the data-mining of their lives truly is, until an uncanny recommendation pops up. Facebook isn't scanning the work email of the attorney above. But it likely has her work email address on file, even if she never gave it to Facebook herself. If anyone who has the lawyer's address in their contacts has chosen to share it with Facebook, the company can link her to anyone else who has it, such as the defense counsel in one of her cases. Facebook will not confirm how it makes specific People You May Know connections, and a Facebook spokesperson suggested that there could be other plausible explanations for most of those examples -- "mutual friendships," or people being "in the same city/network." The spokesperson did say that of the stories on the list, the lawyer was the likeliest case for a shadow-profile connection. Handing over address books is one of the first steps Facebook asks people to take when they initially sign up, so that they can "Find Friends." The problem with all this, Hill writes, is that Facebook doesn't explicitly say the scale at which it would be using the contact information it gleans from a user's address book. Furthermore, most people are not aware that Facebook is using contact information taken from their phones for these purposes.

Comments

Re:Thanks, cell provider, for baking it in

[spaceman375]

I disabled facebook on my android phone. I can go back and look at it anytime I want to verify that it says disabled. Funny how it also lets me "Force Stop" the running app, within 2 days of having killed it. With no reboot, no launching or asking permission from anywhere, it just "mysteriously" keeps re-launching, disabled or not.

Re:Geolocation

[tlhIngan]

Well, I don't use facebook much at all - maybe I login a total of once a month (on average - I usually go 6+ months without logging in at all - enough so Facebook sends me emails about how to get back online). I don't have any photos up other my profile photo, which is a scan of an actual photo that was taken ages ago. I didn't have an electronic copy of it.

I didn't install the facebook app on my phone (I don't use it often enough to justify it), neither my iPhone, nor my iPad, nor any of the Android phones I have (which are Nexus models and thus do not come preloaded with it).

And yet, earlier this year, it came up with a really uncanny recommendation - it actually found my flight instructor, someone who I lost contact with about a decade and a half ago when he went on to pursue an airline career (typical pilot career progression - you're a student, then you get your private, you work on your commercial license, then you become a flight instructor until you can get hired by a regional, etc).

Sure, he's active on Facebook, but not only am I not, we have absolutely nothing in common - no mutual friends, etc. Heck, I'm pretty sure I didn't even put the name of the flight school I went to in my facebook profile. And the scanned photo has no geolocation information so it was a scan.

Yet one day I get an email saying he was the top #1 pick of someone I might know.

The photo I have was of my solo - so it's just me, in front of a Cessna 172 (i.e., one of the most generic airplanes out there). I'm not really sure how Facebook put us together, but given the limited data set it can be fairly shocking.