This week, inside Facebook's California headquarters, Mark Zuckerberg spent twenty minutes playing zero-gravity ping pong with the president of Indonesia.

This is how it works at Facebook. Earlier this month, the prime minister of Singapore visited Facebook's new Menlo Park HQ, and he too dropped into the virtual-reality room near Zuckerberg's office so he could strap on the Oculus Rift. But the prime minister of Singapore was more interested in the virtual dinosaurs. As Zuckerberg describes his Oculus-powered ping pong match with Indonesian President Joko Widodo, his point is that the two of them spent twenty minutes in a virtual world doing something together.

"What people care about," Zuckerberg says, sitting just down the hall from Facebook's VR room, "is interacting with another person."

'When you have another person there, the whole thing inherently becomes social.' Mark Zuckerberg

Ever since Facebook acquired Oculus in the spring of 2014, Zuckerberg has described virtual reality as a "social platform" of the future—as the way we'll not only play games and watch movies, but actually interact with each other. "We're making a long-term bet that immersive virtual and augmented reality will become a part of people's daily lives," he told reporters the day Facebook announced the $2 billion deal, saying it had the potential to be the "most social platform ever." That day, these claims seemed a bit of a stretch. I was among the skeptics. But over the last two years, the VR landscape has shifted, moving at least a little closer to the world Zuckerberg has long envisioned.

Part of what's changed is the Oculus Rift itself, offering sensor-lined hand controllers that let you, well, play zero-gravity ping pong. The Oculus can track the movement of not only your head but your hands. The controllers give your body a way to be "present" in the virtual world. As Zuckerberg and Widodo played virtual ping pong, they could see each other and interact with each other—at least in part.

Virtual ping pong is part of an Oculus demo that Facebook calls "Toy Box." It provides a kind of free-form virtual environment where you can not only toy with ping pong paddles and balls but light firecrackers and play with blocks. And yes, more than one person can enter this alternate universe. Zuckerberg calls it a demonstration of how we can interact with the (real) world through virtual reality. "The thing that's really striking is that when you have another person there, the whole thing inherently becomes social," he says. "It's not a game. There's no points. There's no score. There's no objective. But people find ways to interact. And they're novel ways of interacting."

Social Apps for VR

But perhaps more importantly, Zuckerberg's vision now seems closer to reality because so many other tech giants have embraced much the same idea. In October 2014, Google led a $500 million investment in the augmented-reality startup Magic Leap, a cousin of Oculus-style virtual reality. The following January, Microsoft unveiled its own augmented reality headset, the Hololens. All the while, Google was building its own VR effort from scratch, not only offering a cardboard headset that could deliver VR via your smartphone, but secretly building more advanced hardware. And now, it seems, Apple is doing much the same. "This is a thing that people were laughing at two years ago," Zuckerberg says.

Those words—social apps for virtual reality—don't sound quite as strange as they did back in 2014.

This morning, in Barcelona, just before the annual Mobile World Congress, Zuckerberg will appear at a big press event organized by hardware maker Samsung, whose Gear VR headset is based on Oculus technology. Among other things, he'll announce that a new Facebook team, led by designers Daniel James and Michael Booth, will start building "social apps" for the Oculus. He declines to say what these apps might look like. "The big new thing is that we're doing it," he says. And since we're still waiting for the Oculus itself to reach the market, there's reason to wonder how important this effort will really be in the near to medium-term. But those words—social apps for virtual reality—don't sound quite as strange as they did back in 2014.

Chris Dixon, a partner with the venture capital firm Andreessen Horowitz, was an early investor in Oculus, and even he was surprised that Facebook swooped in for the startup when it did. "When we invested, that was not our expectation," he says. "It wasn't an area that was hot." Now the landscape has shifted to the point where he too sees VR as the next big "platform." "Once the prices come down and the quality goes up and developers get hold of it and are able to be creative and create all sorts of new things," he says, "we'll discover that it's for a lot more than just games."

'This Could Be Possible Now'

When he was eleven or twelve, Zuckerberg says, his parents bought him his first computer. And he was obsessed. Sitting in his middle school math class, as the teacher lectured, he would write computer programs on notebook paper in languages like C and Pascal. And sometimes, he would go further. He was would sketch out a kind of VR interface for his computer—something that wasn't yet possible. "Computing shouldn't be this thing where you pull up a webpage or some 2-D thing," he thought. "You should physically feel like you're going to a place."

It was the kind of thought many youngsters have. But then his circumstances changed. "Maybe when I was a kid, it didn't make sense to work on this," he says. "But now, we have this big company, and we kinda like make these bets that are far off into the future." Indeed, in 2014, after "reading a lot science fiction" and kicking the tires on several VR and AR technologies under development in both the commercial world and across academia, he and Facebook spent that $2 billion on Oculus. "The Oculus demo was a turning point in my thinking," he remembers, explaining that the device was so much lighter and, potentially, cheaper than existing VR gear. "It was like: 'This could be possible now.'"

'The Oculus demo was a turning point in my thinking. It was like, this could be possible now.' Mark Zuckberg

But Facebook bought the technology as much for what it could do tomorrow as today. Zuckerberg describes it not only as a social platform, but as the next fundamental computing environment—the step after the smartphone. "There was the PC, then web, then phone," he says. "I think that something like VR and AR is going to be next platform." In other words, it's another way of interacting with our computers—and a way of interacting with the world.

There's a kid-in-a-candy-store vibe to Zuckerberg's $2 billion bet on this virtual future. But Dixon agrees with him, comparing the Oculus deal to Google's acquisition of Android back in 2005. "I remember thinking 'Wow, that's a futuristic investment,'" Dixon says of Google's Android buy. "I remember admiring Google for that, but also thinking: 'It's a little strange.' It turned out to be genius." But that genius wasn't obvious right away. Android needed time to mature. Virtual reality does too.

Facebook says that since the launch of Gear VR in November, people have used the headset to watch over a million hours of video. And Google says that over 5 million Google cardboard headsets have reached the market, with people downloading more than 25 million apps for the device. Virtual reality is, well, real. But Dixon will tell you that these devices stop well short of the experience the Oculus can provide—particularly when paired with its new Touch controllers. This is something, he adds, that the general public hasn't really witnessed.

You can witness it, he says, when you try Facebook's "Toy Box" demo. "It's a really amazing demo," he says. "And the fact that you could have another person in it made it dramatically more impactful." As Zuckerberg says, it's social.

When VR Meets AR Meets Reality

Indeed it is, at least in a small way. The big question that remains is how social VR will dovetail with the rest of Facebook. The company is already adding 360-degree videos into the Facebook News Feed, and Zuckerberg sees this as a step towards virtual reality. Indeed, you can watch them with the Gear VR. But these videos don't require a headset that wraps around your eyes. Virtual reality does. It shuts you off from the rest of the world, and that doesn't necessarily jibe with Facebook, which is really something you use on a phone, while you're doing other stuff—while you're riding on a train to work or waiting for someone to meet you for dinner.

Zuckerberg doesn't quite know how these two paradigms will meld. Or if he does, he's not letting on. But the end game, he says, is a pair of super-lightweight eye glasses that can instantly shift you from the virtual world to the real world—and back again. These could immerse you in virtual reality or they could add digital stuff to what you see in the real world, augmented reality-style. Using these glasses, you could play virtual chess with someone on the other side of the world, he says. Or you could look at still photos someone just sent you on Facebook.

Today, that seems a stretch. At this point, lightweight digital glasses—think: Google Glass—still look like a failure. But in a couple of years, this will all sound a lot more real.