We are now entering a new era in computing. Some call it ubiquitous computing, others call it augmented reality or wearable computing. We have in the last decades seen major changes.
In the old days we had terminals, then came the personal computer, later laptops that made us more free. The tablets, smart phones etc gave us even more freedom, but they have small screens and very small keyboards.
With the coming displays like Google glasses, Moverio, and Oculus Rift you have a new type of screen – it can in the future give you an enormous big screen but the device will remain small. The Virtual keyboard can be the input device for wearable computing. It gives you a keyboard, a 2-D mouse, a 3-D mouse or better a gesture device.
It can of course be used to any computer, tablet or smart phone.