Andy Harris is talking about the future of shopping. 

"We are able to drive a better in-store experience for the customer," he tells a hotel conference room. "VR, as a platform for shoppers, is going to be the way that manufacturers, and the ecosystems around them — Google, Facebook, Apple, et cetera — are going to be interfacing customers. This is the way that people are going to be interacting with the world, going forward."

Harris is speaking at the Augmented & Virtual Reality Applications in Retail & e-Commerce Marketing Conference, in a Marriott hotel next to Heathrow Airport. "My response to people who say, 'Well, is VR just a passing fad?' No, it's not."

Earlier this morning, Jingyi Zhang, from "virtual makeover" company ModiFace, showed us how augmented reality was impacting on the beauty industry. "People don't have to go into a store and try on things to find out what they like any more," she explained. "You don't need some model or some celebrity. You are the new model."

Then it's the turn of Karl Herkt, from a company in Germany called Dassault Systèmes 3DExcite GmbH. The thrust of his talk — that VR can be a powerful platform to tell a brand's story — being somewhat undercut when it's time for questions from the audience. Here, one man volunteers a query that's never too far away from any discussion concerning virtual reality. 

"My question is about sex," he says, in a thick Italian accent. "What do you think about porno as a new perspective of VR?"

"Um, well, I think… How shall I put this?" fumbles Herkt, to sniggers in the room. "So: the sex industry has always been a great driver for technology and the internet, in terms of streaming video or different interfaces, so I think it's only a matter of time before it… Matter of time."

This year, virtual reality has become a reality. In March, the US company Oculus finally launched its much anticipated Rift headset, the hype around it having grown steadily since the company was bought by Facebook for $2bn (£1.3bn). In April, the Taiwanese gadget company HTC launched Vive, a virtual reality headset developed in conjunction with the PC gaming company Valve. Prior to that, Samsung unveiled Gear VR, a headset that allowed you to experience virtual reality by slipping one of the South Korean phone giant's products into a visor. This October, PlayStation will launch PlayStation VR, an add-on that will bring VR gaming into the living rooms of the 43m people who already own a PlayStation 4. The New York Times has already given away one million sets of Google Cardboard, the budget goggles — literally made out of cardboard — that turn any smartphone into a VR-ready device. In July, Sky TV confirmed that it, too, was on a VR push, launching a virtual reality app, compatible with content from its freshly established Sky VR Studio. 

A good chunk of this summer's Olympics was broadcast in VR. Car companies like Toyota have announced VR schemes aimed at promoting safer driving. Aaron Puzey, a British cyclist, is attempting to ride the length of the UK from his front room, using a stationary bike and a VR headset linked up to Google Maps Street View. At the time of writing, he's just north of Manchester. Perhaps inevitably, Björk is touring a VR Album Exhibition, inviting fans to don headsets and experience her videos in a new way. 

Meanwhile, in Tokyo, there was the world's first adult virtual reality festival. July's Adult VR Fest 01 was shut down virtually immediately due to overcrowding, resulting in a premature evacuation for the thousands of punters who'd turned up to sample a machine in which a virtual woman lay down on top of them, and a cardboard box that blew air in such a way it allowed them to fondle "breasts".

Industry experts predict VR will have its first billion-dollar year in 2016, with $700m (£525m) of that in hardware sales, and the rest in software. They estimate sales of about 2.5m VR headsets and 10m games. PlayStation VR has already sold out on pre-order.

Yes, this is the year virtual reality has become a reality. But what is it? Do we really need it? And is it any good?

Lots of things get described as having to be seen to be believed. It's hard to think of anything that fits that description better than virtual reality. It sounds like a joke. The goggles make you look like a dick. And things like Adult VR Fest 01 aren't exactly great PR. It's almost impossible to describe. The fact is, you really do have to try it. PlayStation, for one, recognises this as an issue. When PlayStation VR launches on 13 October, it will take it on the road to shopping centres and the like, so people can have a go.

"If VR is done well, then the sense of presence, where you actually feel like you're there, is a phenomenon," says Dr Dave Ranyard, an independent virtual reality developer. "And it's something that is very, very hard to describe. I can tell you what it's like, and you can try and put it into words in a magazine. But actually doing it is a transformative experience."

All virtual reality devices are headsets worn like glasses: inside each one is a screen that can display 3D images. The VR headset tracks your head movement and the 3D image moves accordingly. This makes it appear as if you're wholly inside a 3D "virtual" world. The other thing is that you're cut off from everything outside virtual reality — RR, or "real reality", as some developers actually call it. (Life, to you and me.) With a basic VR headset, like Google Cardboard, you can watch stereoscopic videos on YouTube, or scan around a potential holiday location that's been photographed in 360 degrees, like a fancier version of Google's Street View. With a more advanced headset like HTC's Vive, which requires connecting to a powerful PC, you can effectively be placed into the action of an arcade game, your RR movements being replicated in the VR world inside the headset.

Back at the Heathrow Marriott Hotel, we break for lunch and I talk to Andy Harris, who works for the company Fifth Dimension. It specialises in customer experience in the retail sector and tells shops how they can increase their profit margins and customer loyalty. In his Twitter bio, Harris describes himself an "evangelist for retail VR solutions" and he's here today demonstrating a VR programme called StoreView. It allows retailers to build virtual 3D versions of their shops and then play around with the floor plan and try out new ways of stacking shelves. He's got a demo up and running on his stand and encourages me to have a go. The programme runs on Oculus Rift, which was the first of the current wave of VR headsets and seems to have set the aesthetic for all the others: big, boxy goggles secured to the back of the head by thick, rubbery straps. 

Harris helps me in. It's weird immediately. It feels as if I'm wearing a frogman's mask. Harris needs to give me two controllers, but because I can't see him he has to open my hands and physically place them there. On screen I can see a computer rendering of a generic supermarket: aisles stocked with replica everyday items. When I move the controllers into my field of vision they become replica hands. Everything is angular, like I'm in Max Headroom world. It's disorientating. Harris encourages me to pick something up and I reach out with my new virtual appendages to try to grab a jar of coffee. But I'm not doing it right and my computer hand flails about uselessly. Eventually, Harris, who can see what I'm seeing on a TV monitor, takes the controller from me and nimbly plucks the jar from the shelf, rotating it in front of my field of vision. 

This doesn't much feel like the future of anything. But Harris really is evangelical about the possibilities. Once replica virtual stores are linked with e-commerce, he says, it will be possible to wander the shops on a Saturday afternoon without leaving your sofa.

"Because we can collaborate in the same spaces," Harris says, "you can also do it with your mate at home. 'I want to do something fun. Want to go shopping? I'm looking for a new phone, let's go together.'"

I set off back to the office feeling confused. And nauseous.

People have been excited about virtual reality for a long, long time. A 1935 short story by American sci-fi author Stanley G Weinbaum, Pygmalion's Spectacles, considered a goggle-based virtual reality system with holograms that provided smell and touch. In 1957, the pioneering Hollywood cinematographer Morton Heilig developed his Sensorama experience theatre — "the cinema of the future!" — a bulky appliance that resembled an Eighties arcade machine and gave the player the experience of riding a motorcycle through Brooklyn. The Sensorama was able to display stereoscopic 3D images in a wide-angle view, supplied stereo sound and even rocked the player about in a vibrating seat, while blowing wind and smells into their face. (Heilig was unable to secure financial backing to take the project further.) The classic children's toy View-Master, in which thin cardboard discs containing pairs of photographs are inserted into a plastic headset and viewed as a single image, simulating depth perception, is considered an early VR device and dates back to 1939.

Virtual reality became a buzz-phrase in the Eighties and Nineties, thanks to cyberpunks, who championed its possibilities as a means for social change; books like Neal Stephenson's Snow Crash; films such as The Lawnmower Man, Total Recall and The Matrix; and arcade games like Battlezone, which combined wireframe pseudo-3D vector graphics with a rubber "viewing goggle" that the player placed their face into. In 1991, the magazine Computer Gaming World was confidently predicting "affordable VR by 1994". The following year, Nintendo released the Virtual Boy, the first portable video game console to "totally immerse players in their own private universe". It was capable of displaying "true 3D graphics" out of the box but only in monochrome and with a headset so heavy it required a harness. Nintendo declared it game-over six months later, withdrawing Virtual Boy after complaints it caused nausea and maybe worse. One website warned of "sickness, flashbacks, even permanent brain damage".

As a boy growing up in Long Beach, California in the Nineties, Palmer Luckey took these warnings with a pinch of salt. A video game and sci-fi obsessive, by the age of 18 Luckey was taking apart friends' phones and fixing them for money. Before that he experimented with Tesla coils and lasers.

He was also collecting his own personal graveyard of failed head-mounted VR displays, which he'd pick up at auctions. Using a mobile phone and two plastic lenses, and
carting a load of computer hardware around in a bucket, he'd drive from his parents' house to tech shows, where he'd demo his own VR contraption by draping a black T-shirt over users' heads. In 2012, he sought to raise $250,000 in development money on Kickstarter and wound up with $2.4m. "It's nice to find out I wasn't the only nutter," he said. Two years later, aged 21, he sold Oculus VR to Facebook for the aforementioned $2bn. The company now employs more than 360 people with offices in South Korea, Hong Kong, Seattle, Dallas and Silicon Valley. Why did Facebook value it so highly?

"The thing about Facebook is that they're looking at different ways of being able to interact with people and create that social ecosystem," Andy Harris tells me. "They purchased Oculus VR, and then used some of their technology in partnership with Samsung for the Gear VR, so they're trying to get both the high-level 'prosumer' but also trying to conquer the standard smartphone environment. Facebook are betting on an increased social experience with VR down the line. Sharing content and suchlike."

Still, to anyone outside Silicon Valley it might be hard to approach VR without some degree of scepticism. The graveyard of under-loved gadgets seems to have got particularly cluttered in recent years. The reality is that 3D TV has died a death (Samsung, the biggest TV maker in the world, says none of its 2016 models will support the format). Google Glass has been retired. The Apple Watch is conspicuous by its absence. The Internet of Things, where our fridges and ovens are meant to talk to us online, hasn't exactly set the world alight. And for all the big talk, have you ever met anyone who's actually used a 3D printer? Even tablet usage doesn't seem to be what it was, down from a time when every work meeting began with the clatter of iPads hitting tables. We already know we have a problem with our smartphones and the amount of time we spend online: an Ofcom survey, undertaken this summer, found over a third of respondents had taken a self-imposed break from the web, while 59 per cent considered themselves regrettably "hooked" on their devices.

Virtual reality would appear to be an even harder sell. It seems weird — antisocial, and weird. It's expensive, too. The Oculus Rift costs £500, the Vive £760, and that's before you factor in owning a gaming PC powerful enough to pump out graphics at 90 frames per second, the rate required to make VR a fluid, enjoyable and non-nauseous experience. Your existing PC certainly isn't good enough; if you're on a Mac, forget it. Apple doesn't make a machine powerful enough. 

"If they ever release a good computer we will do it," Palmer Luckey has said, responding to the question of when Oculus will come to Apple. (No surprise: Apple is said to be working on its own VR device. In the past 12 months it has filed patents, hired VR experts and bought several VR-related companies.)

Then again, genuinely game-changing new gadgets are always met with suspicion. 

"I think people tend to be worried about every new technology that comes along," Mark Zuckerberg said recently. "Critics worry that if we spend time paying attention to that new kind of media or technology instead of talking to each other that that is somehow isolating. But humans are fundamentally social. So I think in reality, if a technology doesn't actually help us socially understand each other better, it isn't going to succeed.

"You could probably go all the way back to the first books," he continued. "I bet people said, 'Why should you read when you can talk to other people?' The point of reading is that you get to deeply immerse yourself in a person's perspective. Right? Same thing with newspapers or phones or TVs. Soon it will be VR, I bet." 

"We're at the stage we were when the first iPhone came out," Harris says. "We're standing at the precipice of a real step change in how people interact with these platforms. It isn't just a platform for one element. It's a platform for multiple experiences, multiple approaches. It will affect the way that you shop, the way that you interact with people… This isn't virtual reality from the Eighties. It's not Lawnmower Man-style virtual reality."

Still, prophecies such as Snow Crash and The Matrix all posted VR as a warning from the future: dystopian worlds in which what-we-perceive-as-reality is actually a computer programme created by sentient machines to enslave the human race. Nobody suggested it was any kind of Utopia. Plus, as discussed, the headsets make you look really silly.

To that point, last year Time magazine ran an in-depth profile of Palmer Luckey, photographing him for the cover, apparently on a beach, but posing as if lost in rapture, arms aloft, bare feet off the ground, joyful head boxed into his Oculus Rift. It spawned so much Photoshopped mick-taking online — Luckey superimposed on the "Gangnam Style" video, Luckey being held by Leonardo DiCaprio off the bow of The Titanic, Luckey as the Grinch — that the magazine ran a follow-up article, "Here are 37 of our Favourite Time Virtual Reality Memes".

And yet… there is Pokémon GO. The runaway craze of the year isn't virtual reality, it's augmented reality — Squirtle, Wartortle and the rest are superimposed over the real world, they don't appear in their own fantasy world — but given that it took Pokémon GO six days to become bigger than Tinder or Uber, it would at least suggest an appetite for this kind of thing. The immersion could be key: VR as a well-timed balm against the evils of the world. It also commands complete attention from the user. You can't check emails or post to Instagram when you're in it. In our increasingly multitasking lives, might VR offer calming respite?

"It's only when people put the headset on, they get it," Brynley Gibson says.

I'm at PlayStation's offices in London, about to be given a demo of PlayStation VR Worlds, the almost-finished set of five games that will come with its VR headset.

"The inhibitions go," Gibson says. "People forget the world around them. It happens a lot, when they've had something that's so beautiful, so awe-inspiring that they're just lost in it. It's one of VR's magic things."

Gibson tells me the first game I'll try is a passive one. I'll just stand there and look around in 360 degrees, to get a sense of immersion. He helps me on with first a headset, then some headphones. Compared to the Oculus, PlayStation's device has more of its weight distributed around the back, apparently as a concession to Japan where too much weight on one's nose is deemed a problem. It's certainly more comfortable. 

The game starts and I'm in the sea, in a cage, slowly, slowly descending. It doesn't actually look like the sea, because everything is rendered in computer graphics. It's believability over realism. And the feeling of descent is absolutely believable. My head functions as the camera, as advertised. Everywhere I look — behind me, to the floor of the cage beneath me, and the roof of the cage above me — marine life seems to come alive: dancing shoals of tropical fish, gently swaying coral reef. But Gibson hasn't been entirely honest with me. The purpose of the cage becomes apparent as a 12ft great white shark hoves into view. First it glides past the cage — I follow as it goes behind me, and turns back — then it bumps the cage. Then it rams the cage. Then it pulls the door off. I yell out, the cage starts to ascend and the game ends. 

I don't mind that I'm in a room with people I don't know having been tricked into yelping at a computer shark. I no longer care about what the headset looks like. It's the most incredible fun.

"We had someone in the other month and they really lost it," Gibson smiles. "I looked into her eyes and said, 'Do you want to come out?' And she was, like, 'No! I'll go back in!' She was shaking at the end."

The shark bit is part of a bigger game called Ocean Descent. When it comes out, PlayStation says it will be clearly named.

"We're calling it Shark Encounter, that version," advises Gibson. "So it's really clear."

I try further games: The London Heist, where I'm a passenger shooting from a car window as rival gangs screech past all around me (amazing). Danger Ball, in which I bat a ball back and forth in a futuristic arena using my head (fun). And Scavenger's Odyssey, the most hardcore gamer-y of the offerings, where I'm maneuvering an alien craft along treacherous alien terrain (tricky).

PlayStation has been working on its VR offering, until recently known as Project Morpheus, since at least 2011. Because a global audience of millions owns a PlayStation 4, a powerful gaming machine already designed to pump out the same high frame rate required to make the VR experience fluid and enjoyable, and which also has the controller and tracking camera Oculus and Vive users will require, it's got an enormous head start. After an hour using it I also don't feel sick. (Which is a plus.)

"It's been a focus for us to try and make the experience as comfortable as possible," says Gibson. "You're doing a lot to your brain. We're doing 3D, so there's potential strain when you're focusing your eyes. If you drop below a certain frame rate you will make people nauseous. Also: different people are triggered by different things, it's not like there's some hard and fast rule."

The way the car swerves around the road in The London Heist may look random or thrown together, he says. In fact, it's a careful balancing act between what looks cool and what feels comfortable.

Later, I visit SIE London Studio, Sony's in-house developer, which has spent the past few years developing PlayStation VR Worlds. Inside, under subdued artificial lighting, dozens of programmers, artists, designers and engineers sit at low desks littered with computers, soft drink cans and VR headsets. There I meet Russell Harding and Joel Smith, the project's creative director and art director.

"I've had great moments in traditional gaming where I feel exhilarated or sad or happy but the emotional impact you get with VR is different, it's almost like a multiplier," Harding tells me. "Ocean Descent is kind of awe-inspiring at first. I mean, Joel cried."

"It's about that feeling of true immersion, that feeling of, 'Yes, I am in this world'," Smith says. "That was where the tears were coming from. Not just visuals, which were mine, but the sounds and all the emotional triggers. That was the thing for me."

Harding highlights something rather less dramatic but equally affecting, from The London Heist. (It sounds a bit mad but by now I'd come to understand what he means.)

"There's a scene where you get to open drawers in a desk, which in itself is really powerful, weirdly. In a game we normally say, 'Press X to open drawers'. This is, like, 'I'm opening drawers. I'm looking inside.'"

Simon Adderley is a self-confessed serial entrepreneur. He was the first person to bring car flags to this country. Now he's opened the UK's first virtual reality centre, Tension VR. It looks like a converted church that someone's painted black because that is what it is. It's in Lincoln next to a fishing tackle shop. We stand outside and admire it. 

"I was fairly certain I wanted to be in Lincoln," Adderley says. "It's got the cathedral and the cutting-edge university, that blend of history and technology. In a way, Tension is a microcosm of what Lincoln is. I like to think we're a great complement to it."

Inside, there are sci-fi paintings by a local artist on the walls, blue strip lighting that recalls a TV spaceship set and four themed rooms each containing an HTC Vive VR machine. The overall effect is reminiscent of a karaoke club: somewhere you can rent a room (£40 an hour per group) and take it in turns pretending to be somebody else, while your mates look on.

"My son is a massive gamer," Adderley says. "It's how we get quality time together. He's got no interest in anything I do, so I've got to go where he's at." 

Five years ago, they went to Gamescom, a Cologne-based video games conference, and saw the Oculus Rift prototype.

"I said to someone from the company, 'It's a game-changer.' I wasn't sure what I could see, but I could see it was a game-changer. I wanted to be the first and I wanted to have the knowledge that no one else had."

Adderley is as keen on the potential therapy, healthcare and education possibilities of VR — he'll soon be off to America, to pick up some Google Expeditions kits, designed to give kids virtual tours of everywhere from coral reefs to the surface of Mars — but for now he's all about the games.

While the PlayStation VR is stationary, designed to be played sitting down, or sometimes standing up, but not necessitating too much moving about, HTC Vive demands it. It requires you to be hooked up to a PC and to remain physically attached to it by a cable. It also requires an empty room measuring 15sq ft, since this is the tracking space measured out by laser sensors, placed in the corners of the room, that will track your movement with precision, allowing you to move around in a virtual game space. (The headset alerts you when you are near a real-world wall.)

This is the moment I'm totally sold on VR. The fact that you're physically in the game, jumping around, is extraordinary. In Longbow Tower Defense I become an archer firing arrows from a quiver, the tension of the bow and arrow felt in the controller's haptic feedback. In Audioshield, my hands become glowing shields as I bat away colour-coded flaming balls, streaming towards me in time to the beat of pop songs. It's exhilarating, a more physical take on Rock Band. (I'm sweating.) Finally, in The Brookhaven Experiment, I become a zombie hunter, shooting the undead as they stagger towards me from all directions, including — arggh! — behind.

"Tension is here to bring VR to the people," says Adderley, who envisages Tension VR centres up and down the country. "Seeing people's reactions, the pleasure they get from it, is amazing."

Of course, VR isn't just about games. It has already been used in applications as diverse as surgical training, where it's been shown to
improve operating room performance, or
to highlight the plight of refugees, as in Clouds
Over Sidra, an eight-minute film created for the United Nations in which a 12-year-old girl guides you through her temporary home, the Zaatari Refugee Camp in Jordan, housing 130,000 Syrians. VR has been used to help war veterans overcome PTSD. And to help stack supermarket shelves. And to simulate the feeling of a woman's breasts. One of the most talked-up areas is business, where, instead of using the phone or Skype, it will be possible to converse in VR: to shake hands, pass one another documents, and for two parties to study the same 3D model. 

"We don't know how it'll flourish yet," says Dr Dave Ranyard. "It's a bit like when you got the first computers, when home PCs came out. People bought big reference encyclopedias [on CD-Rom] for them. I don't think anyone used them, but clearly the excitement for the possibilities was there. Now you can't really live without a computer and the internet."

But it seems likely that "the entertainment space" — games, films and events, being able to be "there" at the Olympics opening ceremony, or front row at a Beyoncé gig, for instance — will drive VR forward. 

Damien Henry invented Google Cardboard with his colleague David Coz. Engineers at the Google Cultural Institute in Paris, they had come up with the idea during "20 per cent time", a scheme where employees are encouraged to spend a fifth of their
salaried time on a creative project of their choosing. Google Cardboard is the flip-side to HTC's Vive. It's so cheap, Google actually gives it away — the pattern for cutting your own goggles is online. (Or Amazon will sell you a ready-made pair for a couple of quid.) What Henry and Coz grasped was something Steve Jobs apparently missed. That the tech involved in making a high-end smartphone is also the tech required to make convincing VR. Most of us have been carrying a VR-ready machine around in our pockets for the past few years.

"The key is the high-quality screen," Henry explains. "So that you can split the screen in two, and put two magnifying lenses in front of it. The other thing is the gyroscope. Your phone is already able to calculate the position of where you are looking."

Henry worked out that if you could support a phone in just the right position in front of two lenses then you could view stereoscopic content. (There's loads of it online, YouTube has a "360 degree" channel.)

Having found pizza boxes too greasy, they tried out other types of cardboard. "We were surprised how rigid it was. We said, 'OK, we don't need plastic.'"

They presented it to Google HQ in Mountain View, California, and Larry Page green-lit it that day.

"If you did a helmet, it's in plastic, nobody cares. If you say, 'Hey, I did something for VR in cardboard', then everybody is, like, 'What the fuck?'" Henry says. "Then you get attention."

We are talking in the Cultural Institute, a magnificent former stables to an old Parisian mansion and a 340sq m dedicated annexe of Google France's office. Amid the blue-red-yellow-blue-green-red Google branding everywhere and the preposterously well-catered free staff canteen, the internet giant is creating high-definition copies of the world's greatest artworks, using the 360-degree cameras-on-a-stick recognisable from its Street View cars. In the five years since the project began, Google has digitised more than six million photos, videos, manuscripts and other works of art, culture and history — you can zoom in on any of them online now. 

There are other projects, too. Such as inviting six artists to each create a new work using Tilt Brush, a 3D painting app that Google released in April. Henry invited me to have a demo, and in the foyer of the Cultural Institute I was manoeuvred into an HTC Vive. Before me appeared a work by the graffiti artist Tristan Eaton. It resembled a floating head in a headdress and was the size of a child. But I could walk around it, examine it from all angles, reach out and put my hand into it. Henry encouraged me to go further, to step inside it. Then I was in the middle of the picture, surrounded by dazzling purples and neons. It was so astonishing I cried out. Henry then cleared the picture away and invited me to have my own go. In VR, my left controller become a palette, my right controller a pointer. With my right hand I was able to reimagine painting on paper in a 3D environment. I could paint in 3D strokes, adding to what I was doing as I walked around and through my picture. Tilt Brush allows you to draw anything you want, even the impossible, with "brushes" for fire, snow, stars and smoke. 

Google talks of applications in the fashion industry, where you could paint with textured fabrics and to scale, and in the industrial engineering field, where you could render, say, a concept car. The advantages over pen and paper would seem enormous.

As I danced around the foyer with my Tron headset on, tripping over the cable as I went, hands painting in thin air, I no longer cared if I looked like an ass in the real world. I no longer cared for the real world. I understood VR entirely. I wanted to stay all day but Henry was making noises to leave. 

"I have a meeting," he apologised.

This autumn, Google will release Daydream, a platform that will bring a host of everyday apps into virtual reality. It will also release its own new, non-cardboard headset designed to deliver high-quality VR content. The next generation of phones is likely to be more heavily focused on the creation and display of virtual experiences. And, no doubt, companies of all stripes will continue to court customers with the possibilities of the new tech, some more enticing than others: Budweiser has offered customers VR tours of a brewery, McDonald's has invited them to make a VR headset from a Happy Meal box. Plenty of people have signalled caution over VR, saying that the glasses will never be comfortable over long periods, or warning that it will only be a matter of time before someone creates extreme content along the lines of the Saw or Hostel movies. 

"The power of VR to induce particular kinds of emotions could be used deliberately to cause suffering," as two German researchers wrote recently, publishing a series of recommendations on the ethical design and implementation of virtual reality. "Conceivably, the suffering could be so extreme as to be considered torture."

But many, many more consider it the dawning of great things. 

"VR holds the promise to be even more transformative than the flat web was, reaching into every segment of every market and remaking it to be virtually accessible," as the CEO of one VR start-up has written. The result, he says, will be "a new wave of prosperity that will reach around the globe."

Or, as Andy Harris puts it, "The fact that Google, Facebook, Apple and HTC are getting on board with this means that it's here to stay. No question."