Historically reading was kind of a shared experience. Before press &quot;scribes who copied manuscripts often made marginal annotations that then circulated with the manuscripts and were thus shared with the community; sometimes annotations were copied over to new versions when such manuscripts were later recopied&quot; I&#x27;m quoting <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Text_annotation" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Text_annotation</a> , references 2 and 3. Interestingly reference 3 is this paper <a href="http:&#x2F;&#x2F;jbt.sagepub.com&#x2F;content&#x2F;15&#x2F;3&#x2F;333" rel="nofollow">http:&#x2F;&#x2F;jbt.sagepub.com&#x2F;content&#x2F;15&#x2F;3&#x2F;333</a> (paywalled PDF, sorry) about the future of annotations.