A study looking at the measuring of online advertising systems has thrown up the interesting fact that a feature in Facebook could be revealing users' sexuality to advertisers without their knowledge.
Facebook allows users to specify which gender they prefer in a partner, and it's no secret that Facebook allows advertisers to target particular users on this basis, with ads for gay bars, for instance. If a user clicks on one of these ads, both his sexual preference and unique identifier are revealed.
But the report points out that where users tell an advertiser that they've seen a particular ad on Facebook, if the ad is targetedexclusively at gay people, then the advertiser knows the user is gay. And, they say, the information may be going to many advertisers that users simply wouldn't expect.
Researchers from Microsoft and the Max Planck Insitute set up six fake Facebook accounts. Two were for males interested in females, two for females interested in males, and one each for a male interested in males and a female interested in females.
The age and location were set to 25 and Washington DC respectively.
They found that, while the ads displayed on the gay woman's profile were much the same as those on the straight woman's, there were substantial differences between those on the gay and straight men's.
Worryingly, though, the researchers say, many of the ads appearing on the gay men's profiles weren't related to sexual preference - such as one for a nursing degree at a medical college in Florida, for example.
"The danger with such ads, unlike the gay bar ad where the target demographic is blatantly obvious, is that the user reading the ad text would have no idea that by clicking it he would reveal to the advertiser both his sexual-preference and a unique identifier (cookie, IP address, or email address if he signs up on the advertiser’s site," say the researchers.
"Furthermore, such deceptive ads are not uncommon; indeed exactly half of the 66 ads shown exclusively to gay men (more than 50 times) during our experiment did not mention 'gay' anywhere in the ad text."
Thus, to use the medical school as an example, if a gay man clicks on the ad and mentions that he saw it on Facebook, the school now knows his sexuality.
It's a rather contrived little loophole, and it would contravene Facebook's terms of service. But for a company that's come under so much fire over privacy lately, it is at the least an embarassment.
The report is here.