Over on Boing Boing Gadgets, our Joel's spotted "Tourist Remover," a service that takes the stray tourists out of your shots of famous landmarks.
"Tourist Removed" is a web app that will remove other tourists from the photos you took of landmarks while on vacation as a tourist. All you have to do is take multiple shots of the same location, and Tourist Remover will only keep the bits that stay the same. It's like diff for photos!