The academic used Amazon’s crowdsourcing marketplace Mechanical Turk (MTurk) to access a large pool of Facebook profiles, hoovering up tens of thousands of individuals’ demographic data – names, locations, birthdays, genders – as well as their Facebook “likes”, which offer a range of personal insights.
This was achieved by recruiting MTurk users by paying them about one dollar to take a personality questionnaire that gave access to their Facebook profiles. This raised the alarm among some participants, who flagged Kogan for violating MTurk’s terms of service. “They want you to log into Facebook and then download a bunch of your information,” complained one user at the time.
Crucially, Kogan also captured the same data for each person’s unwitting friends. For every individual recruited on MTurk, he harvested information about their friends, meaning the dataset ballooned significantly in size. Research shows that in 2014, Facebook users had an average of around 340 friends.
This is probably the only presidential blog-post you’ll see from me in 2016.
The way Cambridge Analytica mislead Mechanical Turk workers to authorize Facebook and share friend data with them is downright uncomfortable. $1 for an average of 340 data profiles is probably the cheapest behavioral data anyone has bought all year. I believe that’s 1/5th of a penny per person.