From blogging standards, it ridiculously late to post about Microsoft's Photosynth technology. Its way too old news. But somehow, in the act of serendipity, I came across it recently, and was completely blown away with where this technology can take us. I am sure you will be blown away too. Wait until 4:05 minute into the video, where Blaise Aguera, chief architect of Photosynth, shows how a 3D image of the Notre Dame Cathedral that was reconstructed just using the pictures of it on flickr. You can also visit http://labs.live.com/photosynth/ for a web version that is shown in the video.
If you are short of time, scroll to 4:05 minute mark to see the 3D image of Notre Dame Cathedral.