100 years ago: "Risque" was defined as the lingerie section of a J.C. Penney mail-order catalog.
Tomorrow: A pioneering generation of habitual VR wankers.
Here's my guess: Feeling like you're in the same room with someone who is far away.
Just like smart phones, it wasn't the early devices with clunky hardware, high price tags, and cool features that drove mass adoption. It was the move toward ergonomics and ease of use with a core set of common functions that turned it from a techie thing into something ubiquitous.
I actually think you could probably make a standalone stereo Bluetooth headset/glasses with clear lenses and two lasers that project a single 3d stereo positioned dot onto each lens. You'd just need a chip to position the audio and the two dots so I think you could do a really compact low power device and sell them for <$100.
You could just walk around your house, and the dot would stay close to you and talk to you and you would feel like they were in the house with you, rather than inside a little phone.
I ask because I wonder whether the overhead of using the device is outweighed by its value as a communications tool.
In the last go-round of VR, the killer app was supposed to be the Multiverse (as in "Snow Crash"). Now that Second Life is available but slowly sinking, that doesn't seem as compelling. The problem with Second Life doesn't seem to be graphics resolution, lag, or anything technical; it just isn't worth the trouble. There's an Oculus Rift client mod for Second Life, not that anybody cares. (The Second Life people should do a WebGL client; more people might try it.)
Interestingly, in the first round of VR, back in the 1980s, it was "gloves and goggles", so you could actually do something while in there. This time, the gloves seem to have disappeared. The stock controller is the XBox game controller, although there's an optional wrist-tracking controller. Full finger tracking, no.