For example, the odd practice you still see of finding a blank page or two at the front or back of a traditionally-published book. As Mental Floss explains, because of the way books are put together in “signatures”—individual bundles of pages that are bound together—their pages need to be evenly divisible by four. If there’s an extra one or two pages over the nearest multiple of four, then the book has to have an extra two or three blank pages to make another four.
A lot of publishers have come up with tricks for using those extra pages up—the catalogs of other books you could order in the back of old paperbacks, for example, or those self-indulgent full-page spreads of blurb quotes about how good an author’s other books are that you often find in the front of books these days. Or they just leave the blank pages there as a place for people to draw pictures, scribble notes, or whatever. One book layout artist even told Mental Floss that some self-publishing authors have asked him to leave blank pages on purpose. “They think it’s just tradition.”
Of course, e-books don’t have that “signature” problem. They can be exactly as long or as short as their authors want. So you never know—given a few more decades, perhaps those pages of blurb quotes or book catalogs will be extinct.