Browsing through books, you find one you like, and you´re intrigued by the author or the topic. Using Thrrum, your camera phone can just snap a picture, and it will tell you more about what you´re looking at. Your phone will dig up nice facts like the price, the publisher, the date of publication, and whatever else you might find in a library catalogues. Presumably, you can do this with things besides just books (like movies, for instance).