However, if you want to share those book notes with even one other person, suddenly the whole situation changes. There is a chasm that separates any two minds. You have no idea what the other person knows, remembers, or understands. You now have to add a considerable amount of context and structure to make sure they have a shot at understanding what your notes contain. Now expand that to dozens or hundreds of others, and the effort needed to make that knowledge intelligible explodes.