A couple of days ago, computer journalist John Brownlee wrote an essay about it explaining why he found it disturbing . I'd like to propose that it is symptomatic of a really major side-effect of our forced acculturation into Facebook's broken model of human social interaction—a broken model shared by all the most successful social networks, by design—and that it is going to get much worse, until it kills people. Quite possibly in very large numbers .

First, a quote from John's essay on the subject of "Girls Around Me" ( I strongly suggest you go read the whole thing, both for his analysis and for some screen shots showing what it looks like ):

Girls Around Me is a standard geolocation based maps app, similar to any other app that attempts to alert you to things of interest in your immediate vicinity: whether it be parties, clubs, deals, or what have you. When you load it up, the first thing Girls Around Me does is figure out where you are and load up a Google Map centered around your location. The rest of the interface is very simple: in the top left corner, there's a button that looks like a radar display, at the right corner, there's a fuel meter (used to fund the app's freemium model), and on the bottom left is a button that allows you to specify between whether you're interested in women, men or both. It's when you push the radar button that Girls Around Me does what it says on the tin. I pressed the button for my friends. Immediately, Girls Around Me went into radar mode, and after just a few seconds, the map around us was filled with pictures of girls who were in the neighborhood. Since I was showing off the app on a Saturday night, there were dozens of girls out on the town in our local area ...

Now, here's the point.

What "Girls Around Me" does is simple: it looks up your GPS location, then queries Facebook and FourSquare for people matching a simple search criterion (are they female?) who have checked in (or been checked in by their friends) in your vicinity. It then makes it really easy to pull up their publicly visible information—stuff such as age, occupation, favourite sports, what school they attended, and so on. All the stuff Facebook encourages you to share.

You can probably see why John and his friends became increasingly uneasy about this app: it's pitched as innocent, slightly hokey fun, but it stops being amusing the instant you imagine it in the hands of a stalker or serial rapist. Or even just an unscrupulous ass-hat in search of a one night stand who isn't above researching his target's taste in music and drinks without their knowledge.

Unfortunately you don't need a special purpose tool like "Girls Around Me" to do this, if you have a reasonably powerful Facebook query tool and know how to use it. I can't stress this strongly enough: the problem was not invented by SMS Services O.o.o. of Russia, who wrote the app. And banning the app will not make the problem go away.

What "Girls Around Me" does is make clear just how useless Facebook's security settings are. In theory if you know what you're doing you can disclose your personal information to Facebook and prevent FB from sharing it with strangers. But in practice ordinary people are not all Bruce Schneier. Ordinary people with Facebook accounts tend to over-share personal information because our social instincts encourage us to share information with everyone we can see, and to discount abstractions (such as the possibility that software bots thousands of miles away might be harvesting the photographs and information we put online in order to better target advertisements at us—or worse).

The problem is this: all social networks run on the principle that if you're not paying for the product, you are the product. They operate as profitable businesses because they encourage users to channel their social interactions via their network, perform data mining on the interests that users disclose, and present the users with advertisements tailored to their interests (which are consequently much more likely to result in a successful sale).

However, to make such micro-targeted advertising practical, the social networks need to motivate their users to disclose information relevant to advertisers. There's no point marketing bacon to Jews or Muslims, so religion is relevant. There's no point marketing turkey to vegans or wheat products to coeliacs, so dietary preferences and medical conditions are relevant. If a user is a member of a subculture associated with a distinctive clothing fashion, that information is relevant to garment vendors. And so on. So Facebook, Orkut, G+ and so on all attempt to induce their users to maximize their self-disclosure and to tie their accounts to as many useful third-party information sources as possible.

You may have noticed that Facebook provides privacy controls, for those who are sufficiently worried about stranger danger to want some illusion of control. Unfortunately the vast majority of people have no idea how widely visible "show to all" really is, or that it might enable the users of apps like "Stalking Targets Around Me" to identify and track them. And it is not in Facebook's commercial interest to promote the use of privacy controls. If someone is using the privacy controls with all the settings jacked up to 11, it becomes very unlikely that long-lost friends and relatives will be able to make contact with them through Facebook. Which is a lost advertising opportunity, and therefore detrimental to the revenue stream.

We are encouraged to over-share, for commercial reasons (just as we are encouraged to over-consume, but that's an issue for another time). We are discouraged from imposing reasonable limits on access to our shared information, again, for commercial reasons. (And the mechanism employed for discouragement is a combination of benign neglect and ignorance on the one hand, with behavioural marketing on the other—"if you tell us where and when you went to school we can put you in touch with your long-lost high school friends!")

Moreover we are actively discouraged from maintaining any separation of spheres of identity. Facebook was written by students, for students; one of its pernicious hallmarks is that it assumes that human beings possess but a single identity (which can be harvested by Facebook, needless to say). Ask any teacher whether they want to share their private life and relations with their students! Or parents with children, for that matter. Real human beings live complex lives in which they occupy different roles which are exposed to different people. Facebook tries to bundle everything up into one amorphous blob, and makes it relatively hard to hold information back from some categories. (G+ at least comes with the concept of circles, which is an improvement; but is it sufficient? After all, Google—like Facebook—is essentially the photoluminescent lure dangling in front of the sharp-toothed maw of an angler fish advertising company.)

It's easy to imagine how we could make something worse than "Girls Around Me"—something much worse. Facebook encourages us to disclose a wide range of information about ourselves, including our religion and a photograph. Religion is obvious: "Yids Among Us" would obviously be one of the go-to tools of choice for Neo-Nazis. As for skin colour, ethnicity identification from face images is out there already. Want to go queer bashing? There's an algorithm out there for guessing sexual orientation based on the network graph of the target's facebook friends. It's probably possible to apply this sort of data mining exercise to determine whether a woman has had an abortion or is pro-choice.

In the worst case, it's possible to envisage geolocation and data aggregation apps being designed to facilitate the identification and elimination of some ethnic or class enemy, not only by making it easy for users to track them down, but by making it easy for users to identify each other and form ad-hoc lynch mobs. (Hence my reference to the Rwandan Genocide earlier. Think it couldn't happen? Look at Iran and imagine an app written for the Basij to make it easy to identify dissidents and form ad-hoc goon squads to proactively hunt them down. Or any other organization in the post-networked world that has a social role corresponding to the Red Guards.)

But as I said earlier, the app is not the problem. The problem is the deployment by profit-oriented corporations of behavioural psychology techniques to induce people to over-share information which can then be aggregated and disclosed to third parties for targeted marketing purposes.