Commonplacing facilitates reflexive thought.
Regarding a “commonplace book”, mentioned in chapter 4 of Where Good Ideas Come From by Steven Johnson.
In the early 19th century, “gentlemen of letters” often kept a commonplace book, which meant they recorded the interesting ideas and passages of text they encountered in their studies, in order that they could recollect it faster in the future.
This is very much how I use my Tumblr.