Since I was in college, I've kept a commonplace book. In those days before photocopying, if one borrowed a book and came across a passage one wanted to remember, it was necessary to write it down. It also contains things I've cut out of magazines or newspapers and fortune cookie fortunes.
"A commonplace book is what a provident poet cannot subsist without, for this proverbial reason, that 'great wits have short memories:' and whereas, on the other hand, poets, being liars by profession, ought to have good memories; to reconcile these, a book of this sort, is in the nature of a supplemental memory, or a record of what occurs remarkable in every day's reading or conversation. There you enter not only your own original thoughts, (which, a hundred to one, are few and insignificant) but such of other men as you think fit to make your own, by entering them there." --from "A Letter of Advice to a Young Poet" by Jonathan Swift
Periodically, I like to look back through the books (there are two now) and revisit some of the things I've saved. Often the words will connect with an image or a thought I've had floating around in my brain to spark an idea for a quilt. That's exactly what happened when I reread an Andrea Dworkin quote and was thinking about my friend and my mother-in-law suffering from breast cancer. Here's the original post.