In
Rainbows End Vernor Vinge describes an example of Augmented reality, where everyone wears VR glasses or contact lenses and see the real world overlaid with helpful informational popups, virtual characters, improved architecture, or alternative fantasy landscapes with gryphons wherever a bus is, etc.
Other authors have taken the idea further, and assume people will move permanently in a semi-virtual world overlaid on reality. Others have taken the idea less far and imagined only occasional non-realistic information pop-ups.
When I read this, I imagined it being in a futuristic future 30-100 years ahead. But now I suddenly realise that with google street view we could buid it *right now*. Not with fully-fledged alternate worlds and full-time immersion (which may well be a red herring), but something with the same basis. It seems like there are notable engineering challenges left but not necessarily any _conceptual_ challenges. Imagine needing:
1. A smart-phone with GPS which can find all google streetview images within (?) metres and let the user scroll between them
2. A wiki-like system for creating (one or multiple) overlays of streetview image that can be edited from a computer
3. Lots and lots of bandwidth
3. Image matching to turn an image from the phone's camera into the corresponding overlay
4. Separate overlays for different purposes, eg. one designed for owners of property depicted, one for a community "decorate the world to look like the discworld" project, one for friends-of-friends-of-friends, one for travel guides, one for everyone etc.
5. Automatic alerts for various information.
Imagine being able to just hold your smartphone up to a restaurant and on the screen see the same thing, but with "warning, overpriced" scrawled on it or up to the colleseum and see someone's painting of it as the original, or up to a complicated junction and see a big highlight on the correct path to take!
Obviously that's a lot of work, there's no reason for it to happen like that, but it feels possible, which is scary in itself!
And if it DID work, it would be easy to get people to submit further photos of streets (to cut the dependency on google) and of countryside, interiors, etc.