|a mixed reality scene from the HTC Vive promo video|
One problem with VR is that unless you've tried it, it's very difficult to convey what it's like. Videos of the user's point of view pale in comparison to the actual experience. For example, there are YouTube reaction videos of people watching VR horror experiences. To an observer, their seemingly exaggerated reactions are often comical. That is, unless you yourself have tried VR -- in which case, you'll understand perfectly why they're reacting that way.
What does work for representing VR is a mixed reality video showing the user within the VR environment. HTC used that technique in its promo video for the Vive:
There are a couple of games on the HTC Vive that make it possible to do that, namely Fantastic Contraption and Job Simulator. Here's a sample from Fantastic Contraption:
The good news is that the spectator mode that makes mixed reality videos possible will soon be an added capability for games that use the Unity or Unreal engines, according to Wareable. This would be perfect for YouTube or streaming your game to Twitch.
I'm really looking froward to this added capability. I believe it will educate people who haven't tried VR and perhaps encourage them to try it out to see what it's really like and perhaps persuade them to get a VR system for themselves.