If you haven't been to Microsoft Live Labs site before, take some time to review their latest technologies.
PhotoSynth is a very cool bit of technology. Here's their description:
Photosynth is an amazing new technology from Microsoft Live Labs that will change forever the way you think about digital photos.
Our software takes a large collection of photos of a place or an object, analyzes them for similarities, and displays them in a reconstructed three-dimensional space.
But to really get a feel for it, you should try it yourself!
From the Deepfish FAQ:
Deepfish is a mobile browsing Technology Preview from Microsoft Live Labs. Deepfish displays content in a view that is closer to the desktop experience. The zoom-able interface and cue map allow you to quickly access the information you care about over the web without ever losing track of where you are.
While you can't download it just yet (the CTP is currently full), there is a video/animation that shows you how it works.
There's not much to directly review with SeaDragon, but it is the underlying technology used to stream pictures in the PhotoSynth project, so you can get an idea of what it can do by trying PhotoSynth.