In less than a week, the mobile game Pokémon Go has become the most downloaded app in Apple’s App Store. Photograph by Chris Helgren / Reuters

It started as an April Fool's joke. Google released a funny video that mashed up Google Maps and Pokémon. The video, released on April 1, 2014, went viral, drawing more than eighteen million views in all. “We thought, Why not try and make it real?” John Hanke said. Hanke is the C.E.O. of Niantic, which was then a project inside Google, developing mobile games using augmented and mixed-media reality.

Two years later, Hanke and his team have turned that joke into a reality. On July 6th, Niantic, which had since spun off from Google to become an independent company, released Pokémon Go—a game that encourages you to get out in the real world and use your mobile phone to catch Pokémon. (Pokémon, if you need a primer, are collectible creatures that players use to battle one another. They were first brought to gaming consoles by Nintendo in 1996, and in the early two-thousands they also populated an animated cartoon and stacks of playing cards that were ubiquitous among preteens.) Within two days of its release, Pokémon Go had been installed on 5.16 per cent of Android phones in the United States. In less than a week it has become the most downloaded app of the moment in Apple's App Store and has started sucking time from our days—forty-three minutes on average, according to SimilarWeb, more than Snapchat and Facebook. It has taken over Twitter, caused roving bands of nostalgic obsessives to convene on public spaces, and created discontent in relationships. To say it has spread like wildfire is to exaggerate the power of wildfires.

For a moment, however, put aside the sudden revival of our interest in Pokémon and consider what this spurt tells us about the future of software and the nature of reality—and how they integrate into what we think of as entertainment.

Augmented reality is the “boy who cried wolf” of the post-Internet world—it’s long been promised but has rarely been delivered in a satisfying way. Augmented reality refers to a view of the real-world environment whose elements are overlaid (or augmented) with computer-generated images and sound. (It differs from virtual reality, where the real world is replaced by complete immersion in a computer-generated space.) I first fell in love with the idea of mixed-reality games in 2011, when I tried a beta version of the game Shadow Cities, developed by Grey Area, a company based in Helsinki. It used locations and people from your real life, and put them in a game-like environment placed over real maps. What got me was how the game turned my real life into an alternative universe, and turned the familiar into part of a fantasy. The game involved walking, which was an added bonus for someone who has struggled with his weight.

I was hooked, and since then have been paying close attention to augmented-reality applications. None of them have gone mainstream, even those developed by IKEA and Lego using augmented-reality technology from Metaio, a company that was later acquired by Apple. Over the past few years, I have seen many examples of companies that combine augmented reality, advertising, and sports, but most failed to impress me, because I couldn’t figure out what they were doing for me. They didn’t make me more productive, like Slack or Quip, and they didn’t provide fun, like Facebook or Clash of Clans.

In 2012, Niantic created an augmented-reality game for Android called Ingress. It became a cult hit, and was released on the iOS platform in 2014. Niantic was looking for its next game when the April Fools' Day joke became a viral smash. It was a sign of what people wanted. "We pitched that to the Pokémon Company, and what we found was that they were thinking along the same lines," Hanke said. (Nintendo owns a third of the Pokémon Company and is also an investor in Niantic.)

Pokémon Go, which involves trying to “catch” Pikachu or Squirtle or other creatures with your smartphone, is an inherently social experience. You need to be walking around—on the streets, in public places—to catch the Pokémon. Open the app and, pretty much wherever you are, you could be alerted that there is a Pokémon in the vicinity. The other day, I had some time to spare at the San Francisco airport, so I started looking. An animated version of Google Maps popped up on my screen, along with indications that there might be Pokémon around. The more you move around, the more creatures you find. I found only one, but I got a good workout. More important, the game made me happy; it had served a real function.

The technology to make this happen is something we haven't seen applied before in gaming. Whereas a typical massively multiplayer online game is decentralized among different servers and players, Niantic wanted to create a single source for its game. This requires extraordinary computing power and a fundamental rethinking of how gaming software is written. If a system is fragmented, all users might not be getting new information at the exact same time. Financial-trading systems also run on a single source, because everyone needs to know the correct price of a stock at the same time. “Since everything is changing constantly, this is more like a real-time financial system,” Hanke said, pointing out that the usage on Niantic’s system was “a lot, even by Google standards.”

Hanke has long been interested in mapping and the interplay of our physical and digital worlds. He was the founder of Keyhole, a startup that was acquired by Google and renamed Google Earth. During our conversation, he pointed out that Google Earth was made possible by a convergence of digital photography, broadband networks, mapping, and the small near-Earth satellites that emerged around that time. Augmented reality, he said, is on a similar track—powerful smartphones, faster and more robust networks, a new generation of computer infrastructure, and data collection are all converging.

For those who have been believers in augmented reality, these are exciting times. Riku Suomela joined Nokia Research in 1999 and started playing around with head-mounted displays to experiment with augmented reality. It was clear to Suomela that it would be a while before the technology went mainstream. "I have been thinking Pokémon Go could be the product that creates the market for augmented- and mixed-reality gaming, and I am optimistic this is happening now," Suomela—who has since started a new company, Lume Games, which competes with Niantic—said. Ville Vesterinen, the co-founder of Grey Area, said in an e-mail that “now is an ideal time” for work on “location-based games (you can call them AR if you like).” He pointed out that the number of people with mobile devices has grown considerably since his company released Shadow Cities.

For the past few days, I have been playing Pokémon Go and thinking about what it means. This weekend I went to the recently opened San Francisco Museum of Modern Art and wanted to know everything about the art and various installations, beyond what was posted on the walls. I felt as if I should be able to lift my phone and get more details on the process of the creation of the art work, rather than having to type a search term into my browser. Pokémon Go had changed my expectations on how to access information. That shift in expectation, perhaps, is the game's true importance.

I keep going back to “Rainbows End,” a book by the science-fiction writer Vernor Vinge. The book, published in 2006, is about a character recovering from Alzheimer's disease and learning to deal with the world around him, but what stands out is the world Vinge created. In his fictional world, computing has become miniaturized to such an extent that it’s almost invisible, woven into bodies and clothing. People interact with computers via myriad gestures. Augmented-reality interfaces replace screens as we know them, making it simple to get access to schematics for an elevator, patient records, or a drawing to fix a car.

“Rainbows End” was set in San Diego of 2025. That might seem too soon, but the future often arrives suddenly. And disruption often starts as a joke.