My neighbor is volunteering at the library and has been telling me all sorts of unbelievable stories about how incompetent they are. He's putting books and dvds back on the shelves, and frequently finds stuff out of order. So I got to thinking how to make that job easier. Would it be possible to construct an rfid chip that carried the category, author, and title, and, when in the presence of objects in the same category, show a blue light? If the book was closest to 2 objects, both of which were either less than or greater than the author and title, it would show a red light, and if one of the objects was lower and the other higher, would show a green light that would indicate that the book should be shelved between the two.
With this sort of chip, you could just run the book along the shelves and find out fairly quickly where it belongs.
I don't know if this would be feasible or cost effective, but it sounds like a cool idea.