Perfectly matching snapshots-in-progress with a photo taken in the same spot a hundred years ago is an awesome idea. Turns out, it's kind of hard. But Adobe and MIT have figured out a way to make it happen more accurately.
They're using a robotics technique called visual homing, normally used to send machines to a specific location, like a charging station, in their new software. The program compares your camera's view to known historical images and will give you positioning and zoom instructions so you can best match the scene, improving on the services offered by current apps like StreetMuseum and sites like historypin.