Crowdsourcing Sousveillance

I wrote recently about Microsoft's amazing Photosynth demo, which shows pictures of Notre-Dame taken from Flickr stitched together automatically to produce a three-dimensional model that you can zoom into in just about any way.

Then I read this:

Madeleine McCann's parents will appeal to Irish tourists to check holiday snaps for clues - while the flat their child was abducted from reportedly sold for half price.

Madeleine's parents Kate McCann, 38, and Gerry, 39, will appear on television to ask anyone who took a trip to Portugal in early May to send photos to British investigators.

It occurred to me that what we really need is a system that can take these holiday snaps and put them together in time to create a four-dimensional model that can be explored by the police - a new kind of crowdsourced sousveillance.

Given that Photosynth is still experimental, we're probably some way off this. I'd also have concerns about handing over all this information to the authorities without better controls on what would be done with it (look what's happening with the UK's DNA database.)