Privacy advocates are questioning Netflix's plan to release "anonymized" data as part of an effort to crowdsource improvements to its recommendation system.
But Netflix says it's confident that the initiative will not compromise customers' privacy. "When we do, it will be completely anonymous," says a Netflix spokesperson. "We've done everything we can to ensure our members' privacy and the security of their information."
For the project, Netflix intends to publicly release data including customers' gender, ages, ZIP codes and previously rented movies. The company hopes that interested researchers will crunch that data to figure out how to better predict users' tastes.
The contest, which was announced this week and comes with a $500,000 prize, is a follow-up to a $1 million competition to build a better recommendation system. On Monday, Netflix awarded the prize in the earlier contest to the seven-person team BellKor's Pragmatic Chaos.
Although Netflix says it won't release customers' names, some privacy experts say interested researchers will be able to determine people's identities from other data that Netflix will make available.
On Monday, University of Colorado law professor Paul Ohm issued a public plea to Netflix to change its plans. "Researchers have known for more than a decade that gender plus ZIP code plus birthdate uniquely identifies a significant percentage of Americans (87% according to Latanya Sweeney's famous study)," Ohm wrote. He added that even without exact birthdates, interested researchers will be able "to tie many people directly to these supposedly anonymized new records."
Ohm says that the planned release might violate the federal Video Privacy Protection Act, which bans movie rental stores from revealing personally identifiable information about consumers.
Marc Rotenberg, executive director of the Electronic Privacy information Center, said that he also thinks Netflix's plans are problematic for many of the same reasons set out by Ohm.
Attorney Jay Edelson adds that Netflix will almost certainly face litigation should it carry out its plans to release users' movie rental lists and demographic information, even if done "anonymously."
"If they do this there will be a class-action lawsuit," says Edelson. "People inside the company are trying to innovate, which is a good thing, but they're not respecting people's privacy." His law firm, Kamber Edelson, has brought privacy lawsuits against Facebook, NebuAd and other Web companies.
Netflix has previously come under scrutiny by privacy advocates. For its last contest, the company released anonymous lists of users' reviews. But two University of Texas computer scientists published research concluding that it was possible to identify users by comparing reviews of obscure movies on Netflix with reviews on Imdb.com that were published under screennames.