From the essay “The Mysteries of Reading,” part of The Case for Books by Robert Darnton (New York: PublicAffairs, 2009), 149-150:
Time was when readers kept commonplace books. Whenever they came across a pithy passage, they copied it into a notebook under an appropriate heading, adding observations made in the course of daily life. Erasmus instructed them how to do it; and if they did not have access to his popular De Copia, they consulted printed models or the local schoolmaster. The practice spread everywhere in early modern England, among ordinary readers as well as famous writers like Francis Bacon, Ben Jonson, John Milton, and John Locke. It involved a special way of taking in the printed word. Unlike modern readers, who follow the flow of a narrative from beginning to end (unless they are digital natives and click through texts on machines), early modern Englishmen read in fits and starts and jumped from book to book. They broke texts into fragments and assembled them into new patterns by transcribing them in different sections of their notebooks. Then they reread the copies and rearranged the patterns while adding more excerpts. Reading and writing were therefore inseparable activities. They belonged to a continuous effort to make sense of things, for the world was full of signs: you could read your way through it; and by keeping an account of your readings, you made a book of your own, one stamped with your personality.
It will be interesting to see (this will be a while, maybe this will just be a blip) how the “networked commonplace book” of contemporary people will be archived and studied. Blogs, tumblrs, tweets, Facebook posts, etc. all show one way in which we move through, read and write through, the world. Social media are, perhaps, fundamentally different than the traditional commonplace book in the sense that they are inherently public, and the material gathered and broadcasted there is used to create an image of ourselves (however subconsciously) through “communication.” The traditional commonplace book was essentially private, meant only for the maker (although who is to say that they were not composed with a future reader in mind). But regardless of intent, of how “honest” they are, all of these social media broadcasts will be useful to researchers in the future.
I know that some libraries that have purchased the archives of still-working artists are making copies of hard drives and emails. I assume that someone has found, or is trying to find, a way to (efficiently) archive social media. I wonder if there are already papers being written that document and analyze the construction of a public figure through social media. We are, perhaps without even being fully aware of it, creating a collective treasure trove of information for researchers in the (near and far) future.