Being reconnected with a long lost relative might seem like an occasion for celebration, but for one Facebook user it has led to some unsettling questions.
The relatives were connected after messaging each other when one spotted the other on the ‘creepy’ People You May Know feature.
The function is designed to help people to connect via the social network – and it did just that for one great aunt and her grand-niece.
Yet it managed to do so without either user having any links to one another, online or otherwise, and Facebook has refused to offer any answers.
Kashmir Hill decided to investigate how Facebook gathers the information it uses to make connections between individual users via the People You May Know feature. It led her to a long lost relative and unanswered questions about data gathered by the social network
In an depth article for Gizmodo, Kashmir Hill set out to investigate how the social network gathers the data it uses to make connections between individual users.
It has previously emerged that Facebook can suggest ‘friends’ who are close by based on your phone’s location, as well as shared contacts and facial recognition from photographs.
Ms Hill kept track of all the friend suggestions Facebook made over the course of the summer, researching who they were and how they might be connected.
She received 1,400 suggestions, around 160 per day.
Around 200 were people she knew, with the rest apparently strangers.
One woman, Rebecca Porter, stood out as she shared the same surname as Ms Hill’s biological grandfather, whom she never met.
Ms Hill’s father was adopted after being abandoned by his father when he was a child.
He didn’t find out the identity of his biological father until adulthood.
Ms Hill decided to contact Ms Porter, who she had also never met, initially by sending her a message on the site to try and work out how the connection had been made.
Mr Porter confirmed she was her great aunt, by marriage.
She had met Hill’s grandfather’s brother 35 years ago, shortly after Hill was born.
But after spending some time chatting over the phone, the mystery remained unsolved.
Writing in her article Ms Hill said: ‘After we finished the phone call, I sat still for 15 minutes.
‘I was grateful that Facebook had given me the chance to talk to an unknown relation, but awed and disconcerted by its apparent omniscience.
‘How Facebook had linked us remained hard to fathom.
‘Not being told exactly how this tool works is frustrating for users, who want to understand the extent of Facebook’s knowledge about them and how deeply the social network peers into their lives.’
Ms Hill and her father lived in Florida, with the Porter family almost 1,000 miles away in Ohio.
Her father had met his great uncle, whom Ms Porter married, after his mother’s funeral, but no one he met used Facebook.
A spokesman for Facebook refused to give any specific explanation for this case, citing its privacy policy. But they did add that more than 100 signals go into making the friend recommendations, and that no one signal alone would trigger a friend suggestion
‘How Facebook had linked us remained hard to fathom,’ she wrote.
‘My father had met her husband in person that one time, after my grandmother’s funeral. They exchanged emails, and my father had his number in his phone.
‘But neither of them uses Facebook. Nor do the other people between me and Rebecca Porter on the family tree.’
Ms Hill decided to contact Facebook to try and find some answers.
In its online guidelines, the Menlo Park firm states that People You May Know suggestions come from things like having friends in common, or mutual friends.
This is the most common reason for suggestions.
It also includes being in the same Facebook group or being tagged in the same photo.
Other factors that can influence suggestions include your networks, for example your school, university or work, and contacts you’ve uploaded.
A spokesman for the company refused to give any specific explanation, citing its privacy policy.
But they did add that more than 100 signals go into making the friend recommendations, and that no one signal alone would trigger a friend suggestion.
Ms Hill added: ‘Now, when I look at my friend recommendations, I’m unnerved not just by seeing the names of the people I know offline, but by all the seeming strangers on the list.
‘How many of them are truly strangers, I wonder and how many are connected to me in ways I’m unaware of.’
MailOnline has contacted Facebook for a comment.