Excellent review of how important that space on the side of paper is to how the world works. How is it important, you say?

Imagine you're a doctor and you're filling out a form for a patient. He tells you that he can't eat that hospital Jello. Ugh. So you scribble a note on his chart saying NO JELLO lest he die b/c the administration didn't see fit to put a Jello checkbox on the form.

Now imagine you're using a computer and there's still no place to put the information. Yikes. Better hope he can adjust fast.

Librarians actually used to use this all the time with card catalogs. You could store all sorts of useful information on the cards for a book. This became a big problem when the card catalogs of big libraries started going digital because there were years and years of stored information that had no official status in danger of being lost. I hope they saved it.