Full-body haptic feedback suits. They're coming -- the question is, what will we use them for? The best paper on the topic appears to be this one. Interesting fact -- the human body's pressure sensors responsible for deep pressure touch, Pacinian corpuscles, can't even tell the difference between pressure and suction, so one can simulate touch simply by using tiny vacuums. Alternatively, miniature actuators could push downwards to create the sensation conventionally. Another, somewhat more advanced way to implement full-body haptics would just be to jack into the brain directly, though I think it could be difficult to justify brain surgery for recreational purposes in the near-term future.
The point of full-body haptic feedback is that it allows virtual communication of touch. I push you in an online game, and you actually feel like you get pushed. To help with the immersion, it would likely be accompanied by convincing VR goggles. We can expect VR goggles before full-body haptic suits because the former is technologically easier. I predict that convincing haptic suits will arrive by 2020.
One of the first applications for such suits will of course be sex. Cybersex with both other humans and NPCs. Will the "haptic resolution" around the groin area be enough? What about moisture? I think that engineers, in their infinite ingenuity, will likely figure these things out. More realistic cybersex with NPCs will mean that people will be less inclined to get boyfriends and girlfriend IRL. How much less inclined? Don't know, but it's worth thinking about.
Because the sensors would only stimulate the very surface, and not go in deep, women could have problems with enjoying the virtual sex. Some sort of teledildonics add-on would be necessary, possibly with lube secretions. I'll leave the details to your imagination.
Masseuses might get more business, although the lack of deep stimulation could make it hard to give a convincing massage. Acupressure would be another app. Of course, virtual sports would become much more exciting, although you'd have to stay within a bounded area so you don't accidentally run into a wall.
Perhaps the most interesting application in sports would be for virtual fighting -- protected from any serious harm by a haptic suit that serves as the intermediary, novices in martial arts could fight experts without requiring a trip to the hospital afterwards. There could even be "difficulty settings", giving experts a harder whack from a weaker punch. The right little girl could even defeat her own father or another adult male, given the right calibrations. Fights could even include "magic", force projections based on hand gestures or similar.
The suit would also enable touch sensations impossible in real world environments. For instance, waves of touch going from head to toe. Hood attachments would let the user feel sensations like wind on the face, although some might feel squirmy wearing a full-body suit that covers their head. The more advanced versions, which would probably require molecular manufacturing to make, could even generate heat or cold. It's likely that VR world designers will come up with fascinating new touch sensations we can't imagine here in 2007.
Full-body haptic suits could revolutionize military training, as well as many trades. Want to learn how to be a blacksmith? A virtual agent could likely teach you. The availability of such suits would revolutionize education and entertainment in general, allowing people to "experience" digging for fossils, flying an F-22 (minus g forces), fighting with swords, visiting an "exhibition of touch sensations", etc.
More mundanely than full-body haptic feedback, "haptic datagloves" would also provide a way of telling the computer where your body is in space, allowing that positioning to be reflected in the virtual environment. This could do wonders for making users feel like they're actually "being there" in the VR environment.
Haptic suits could improve communication for the deaf. In real life, they could be using sign language, while in the sim an artificial voice could provide the appearance of speech. This could allow the person to communicate with a listener via sign language even if they don't understand sign language per se.
Can you think of any other possible applications for this technology?