A few weeks ago, I was in a café across the street from my house, having just put in an order for the first cappuccino of the day, when a woman walked in with her young son. I recognized him as one of the children who is regularly looked after by the same child minder as my own son. The woman, on the other hand, I had never seen before. The boy obviously recognized me, too, because as his mother was placing her coffee order he smiled up at me and said hello. I returned the greeting, using his name, and felt immediately awkward, because as far as his mother was concerned I was just some random man she’d never laid eyes on. Instead of simply leaving that ambiguous and faintly sinister note ringing in the air between us, I decided to tell her that her son and I knew each other from the child minder’s; but, flustered, I somehow managed to introduce myself to her as “Mike’s mum.” I tried to clarify that I was, of course, Mike’s dad, but the chat was by that point completely beyond salvage. We awaited our respective coffees in tense and complicated silence, before going our separate ways.

Since then, I have, thankfully, not run into this woman again, but given the fact that we live in the same neighborhood, and that our sons are in child care together, I probably won’t be able to avoid her indefinitely. I recently found myself thinking of this when I learned of the existence of a smartphone app called Cloak. The app’s tagline is “Incognito mode for real life,” and it offers its users the ability to “avoid exes, co-workers, that guy who likes to stop and chat—anyone you’d rather not run into.” (Facebook’s newly announced Nearby Friends feature does essentially the same thing, though a spokesperson suggested that the app could be used “to make last-minute plans to meet up with a friend who happens to be in the same place you’re headed to.”) Cloak works by linking with your Instagram and Foursquare accounts to uncover the locations of these undesirables and revealing their avatars on a map, thereby empowering you to give them as wide a berth as possible; in this sense, it’s like a contemporary urban version of those maps from the Middle Ages, with their admonitory illustrations of dragons and sea monsters: “Here Be Vague Acquaintances.”

Obviously, Cloak doesn’t really do anything that Instagram and Foursquare (and now Nearby Friends) don’t already inherently allow. In the same way that these social-media services can always be adapted to antisocial ends, Cloak itself can just as easily be used to contrive casual run-ins. But the technology is explicitly marketing itself as a means of social evasion, and this seems to account for its appeal. There’s a certain novelty value in the idea of an anti-social-media app, a kind of satirical inversion of the assumption of gregariousness built into your Facebook and your Foursquare. According to the New York Times, Cloak was downloaded from iTunes nearly three hundred thousand times its first three weeks. Clearly, there are a lot of people out there looking to avoid running into other people.

When I first heard about Foursquare, shortly before its launch, in 2009, I felt preëmptively oppressed by the very notion of such a thing. “Why would I want you to be able to use your phone to hunt me down and socialize with me?” I thought. It never occurred to me, at the time, that I could use this same gadget to actively avoid running into people. If it had occurred to me, I might have invented Cloak on the spot.

So I was curious enough about Cloak to download it onto my phone. I quickly realized, though, that it was essentially useless to me, what with my nonexistent Instagram network and my total absence from Foursquare. (Cloak offers integration with neither Facebook nor Twitter, rendering it even less valuable to the average chat avoider.) And, even if I were a prolific and widely connected user of these services, the app would still only be able to steer me clear of other people who happened to use them, too. “All Clear: There’s nobody nearby,” Cloak informs me as I write, flagrantly ignoring the presence of my next-door neighbor, whom I can see, through my window, has just stepped out for a cigarette.

I find the idea of a genuinely effective chat-evasion technology initially appealing and ultimately troubling. If there were such a thing as a sat-nav device that planned my route from point A to point B while steering me clear of person X or Y, I can easily imagine getting quite a lot of use out of it. And that’s also exactly why I find the idea disconcerting, and why I’m glad that Cloak doesn’t really function for me in any sort of profitable way.

In “River of Shadows,” her book about the pioneering photographer Eadweard Muybridge, Rebecca Solnit writes about how the development of new technologies in the nineteenth century—railroad networks, telegraphy, photography—was routinely referred to by the stock phrase “annihilation of time and space.” This annihilation, she writes, “is what most new technologies aspire to do: technology regards the very terms of our bodily existence as burdensome.… What distinguishes a technological world is that the terms of nature are obscured; one need not live quite in the present or the local.” The Internet has accelerated this process to a remarkable degree, alleviating more fully than ever before the burden of bodily existence. It allows us to be where we are not, but this also means not being where we are. By generating a kind of omnipresence—whereby we are always available, visible, contactable, all of us there all the time—the technologies that mediate our lives also cause us to disappear, to vanish into a fixed position on the timeline or the news feed. (“You are invisible,” runs the weirdly urgent message on my Gmail chat sidebar. “Go visible.”) Existing online means inhabiting a series of cloaks, a whole complex ontology of lurking and attenuated presence. And there is now that strange new sense of guilty truancy from leaving e-mails and phone calls unanswered while conspicuously tweeting or posting on Facebook—a social breach for which we don’t yet seem to have developed any sort of etiquette.

When I open up Cloak on my phone, I see a stylized map of Dublin in night-vision green and black, with a single pulsing dot at its center, just north of the Liffey: the pulsing dot of myself, right at the cloaked location of my presence, or my absence. “0 People,” reads the counter at the top of the screen. “All Clear: There’s nobody nearby” reads like such a strange, sad message, such a lonely thing to have achieved through technological control of our social environments. Looking at that screen makes me want to place my phone face down on my desk, go out into the street, and walk around until I bump into someone I know.

Mark O’Connell is Slate’s books columnist, and a staff writer for The Millions. You can follow him on Twitter @mrkocnnll.

Photograph by Ferdinando Scianna/Magnum.