Suddenly, you're on the roof of a skyscraper, looking down on the city below. The roof is tiny and you're close to the edge and a sense of vertigo sets in. You feel the need to step back before you fall.

But the edge isn't really there. You're really at Facebook's annual developer conference, and there's an Oculus headset strapped to your face. The city and its skyscraper are part of an Oculus virtual reality demo that Facebook is sharing with conference attendees this week at Fort Mason Center on San Francisco Bay.

Yes, it's an impressive experience. You do feel like you're atop a skyscraper in a city not all that different from New York. When my colleague Jessi Hempel entered the same virtual world yesterday morning, she stepped off the skyscraper, knowing that she was really standing in a tiny room at the back of an old maritime warehouse. But when she stepped, she still panicked—"I freaked out," she says—and stepped back.

But there's another thing you notice while standing atop that virtual skyscraper. As you look down, you realize you can't see your own feet. You're completely disembodied. An Oculus employee is in there with you, in the (real) room. But you can't see them. And you feel rather uneasy about talking to them.

This is the gap Mark Zuckerberg must bridge in combining Facebook with virtual reality, now that his company owns the startup that built the Oculus headset. Facebook's official mission is to make the world a more open and connected place. And Zuckerberg says the Oculus is integral to this mission. But the VR of today is rather closed and it disconnects us in many ways—ways that few other technologies have before. Sure, a smartphone has a way of disconnecting us, too. But it doesn't cover our eyes.

Stepping Stone to Virtual Reality

On Wednesday, during his conference keynote, Zuckerberg revealed that Facebook is now testing a kind of 360-degree video that can put you inside recreations of real places, in much the same way the Oculus demo puts you inside wholly imagined places. At first, these "spherical videos" will show up in your Facebook News Feed. You'll be able to "move through" these videos by tilting your smartphone to and fro. But the plan is to eventually push these videos onto headsets like the Oculus.

Zuckerberg says his smartphone videos are a stepping stone to the world of VR. The implication is that we'll eventually spend our days watching not just good old-fashioned internet videos, but completely "immersive" videos streamed through something like the Oculus. But that's an enormous leap to make. It's one thing to open a video on your phone. It's quite another to strap some goggles onto your head.

Yes, the Oculus—and the Samsung Gear VR, where Facebook is already demoing its 360-degree videos—provide a far more nuanced experience than their non-immersive video counterparts. Undoubtably, an enormous number of people will use these headsets for games. And down the road, they'll use them to watch 360-degree video, real footage from sporting events or museums or, yes, sky scrapers. But you wonder how often people will wholly separate from the real world in order to enter a new one. And if they do embrace this as an everyday activity, you wonder if that's a good thing—if it's really a social thing.

Total Disconnect

Mike Deerkoski strapped on a Samsung Gear VR to see the "spherical video" of Facebook's Menlo Park campus, and he was impressed. "You feel like you're there," says Deerkoski, a technical advisor at a San Francisco startup called Depict. But he hesitates when asked how much time he's likely to spend with something like this on his head. "I don't know," he says. "It's a good question."

Another attendee, Hulker Heschberger, points out that 3-D movies—the theater variety—have never really succeeded because of the headwear problem. "It's artificial," he says. And Deerskoski says that although he doesn't necessarily like the idea of goggles on his head, he does like the idea of viewing a 360-degree video on his smartphone, moving it around in front of him to explore the image.

Like so many others, Brian Blau, an analyst with research firm Gartner, who worked in VR for years, sees the enormous potential in head hardware like the Oculus. "How compelling is it going to be to sit beside your favorite movie star or get in a race car with your favorite Nascar driver?" he says. But he too wonders how much this will really bring us together. Down the road, we'll have a completely immersive way of communicating with people across the globe, but maybe something simpler is the better option—or at least the typical option. "Zuckerberg has said that VR is the most social thing," Blau explains. "But in fact, it's not."

Social Separation

Today, Facebook is about so easily sharing what you have with others. But as it stands, VR is about big companies sharing what they have with the masses. Individuals can't build games. They can't afford the 3-D cameras needed to take 360-degree videos. And when individuals strap on the goggles, they're separated from those in their online social network (let alone the people standing beside them)—not drawn closer to them.

What we need is something that lets you seamlessly move between those two worlds. And the answer may lie in the Samsung Gear VR, which is really just a phone with some extra stuff attached to it. In theory, this kind of thing can give us Facebook, but then let us move easily into the world of VR whenever it makes sense.

The trouble is that when you strap on the headset, it still takes you so far out of the real world—something you may not want to do that often. But as Herschberger says, this kind of hardware will evolve. It will shrink down to something tiny, something that will fit on a pair of ordinary glasses that don't completely separate us from this world, something like, well, Google Glass.

Of course, people don't necessarily like that idea either. Virtual reality is here. But there's so much to sort out.