A Commonplace Book
Long before blogs, people jotted down their thoughts in a blank book. Readers, writers, and students during the Renaissance, particularly in England, used commonplace books to record ideas and quotations.
Commonplacing is the act of selecting important phrases, lines, and/or passages from texts and writing them down; the commonplace book is the notebook in which a reader has collected quotations from works he or she has read. Commonplace books can also include comments and notes from the reader; they are frequently indexed so that the reader can classify important themes and locate quotations related to particular topics or authors.
My own commonplace book is a purple, unlined, wirebound notebook. In it, I have written interesting poems I've read or ones of my own creation. I use it to keep notes from my readings. I copy song lyrics I like. It is a log of all of the interesting knowledge I have come across. This blog is also a commonplace book to me. I record information that is important to me.
You can learn more about commonplace books and the art of commonplacing here and here.