Cedric pointed me (again) at a great piece of technology currently emerging from
Microsoft Live Labs. Photosynth is a piece of software which takes a collection of photos and constructs a 3D space with them. It allows you to move around in this space, see similar photos and take a tour through constructed imagery from a set of photos. The website has a couple of videos showing this off and extrapolating the idea in a future scenario when this software could index all the photos on the Internet and come up with virtual places for people to explore. Exciting stuff!
Microsoft Live Labs: Photosynth