The Department of Defense recently posted a call for proposals—due by September 25—to combat “the national security threat posed by public data available either for purchase or through open sources.” For its only example, the DoD pointed to a 2009 lawsuit against Netflix for allegedly outing a lesbian after programmers reverse-engineered the site’s famously robust recommendation engine:

The Netflix Challenge in 2009 was launched with the goal of creating better customer pick prediction algorithms for the movie service. An unintended consequence of the Netflix Challenge was the discovery that it was possible to de-anonymize the entire contest data set with very little additional data. This de-anonymization led to a federal lawsuit and the cancellation of the sequel challenge.

Foreign Policy notes the film that prompted the federal lawsuit was Brokeback Mountain, Ang Lee’s 2005 adaptation of E. Annie Proulx’s cowboy novella:

Things went off the rails when a pair of researchers used supposedly anonymous information provided by the company to identify Netflix customers, by comparing their film reviews with reviews posted on the Internet Movie Database. A closeted lesbian who had watched the award-winning gay cowboy flick sued Netflix, alleging her privacy was violated because the company had made it possible for her to be outed.

Yikes. It’s a bit unclear, however, how this particular application of aggregate data would be used to weaken the country’s security apparatus beyond the old gay-blackmail trick. Is there really some national vulnerability to be gleaned from the fact that I rented Dead Poets Society more than once? Furthermore, Netflix’s data disclosure was historically unique: you don’t see most other companies (AOL excepted) releasing large amounts of granular user information anymore. The data are too valuable.

The real threat, the DoD posting suggests, may exist within those seemingly sketchy but nonetheless immense databases hawked by websites like Intelius and ChoicePoint, along with the big three credit-reporting bureaus, which routinely sell your comprehensive consumer profile to advertisers. Really, your Weekend obsession is probably the least of your worries.

[Foreign Policy]