Oh but that experience would be so much worse if it were like genius.com where you see the most upvoted annotations. The beauty of reading somebody else's margi

Oh but that experience would be so much worse if it were like genius.com where you see the most upvoted annotations. The beauty of reading somebody else's margin notes is that you learn something about that person not just what they have to say about the book. But if you limited the social experience to friends, people would be self conscious about what they wrote in the margins. And some people would have friends who didn't mark up their books and miss out on the experience. No one's going to buy your damn annotations though unless you're some kind of celebrity. And that's precisely what they'd be buying. In the used book store you're buying the book with the annotations because it's cheaper than the book without annotations, and then you luck out and the annotations are interesting. With ebooks, a second hand purchaser would be able to turn off your annotations and have the original book, good as new, so the price would be, at a minimum, the original retail price.