"What is it about my data that suggests I might be a good fit for an anorexia study?" That's the question my friend Jean asked me after she saw this targeted advertisement on her Facebook profile:
She came up with a pretty good hypothesis. Jean is an MIT computer scientist who works on privacy programming languages. Because of her advocacy work on graduate student mental health, her browsing history and status updates are full of links to resources that might suggest she's looking for help. Maybe Facebook inferred what Jean cares about, but not why.
Days later, I saw a similar ad. Unlike Jean, I didn't have a good explanation for why I might have been targeted for the ad, which led me to believe that it could be broadly aimed at all women between the ages of 18 and 45 in the greater Boston area. (When I clicked to learn more about the study, this was listed as the target demographic.)
Still, it left us both with the unsettling feeling that something in our data suggests anorexia. Ads seem trivial. But when they start to question whether I'm eating enough, a line has been crossed. I see similar ads plastered across the Boston T recruiting participants for medical studies on diabetes, bipolar disorder, and anxiety, but their effect is materially different. The only reason I see those ads is because I ride the T. These messages offer the opportunity to self-select for eligibility. It's different online, where I am supposed to see ads because something about my data suggests that they are relevant to me.