Not convinced that virtual worlds wont make it - but on smartphones.
People txt, not because thats the best way of communicating but because it's the lowest common denominator - everybody has text.
When all the kids have smartphones with GPS/cameras/3G/motion sensors then it's not clear that they wont want a richer environment, and the phones/pads now have the CPU+graphics+bandwidth to allow it.
The main problem is that the environment has to add something. Currently all the virtual worlds - except for the games - made things harder. You had to walk into the virtual post office to send an email in one system.
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