Each entry is preceded by the date the entry was made, and followed by a reference to the source.
Because I’ve used some of the material multiple times I’m vaguely aware of the overall structure, and I use it as a bit of a knowledge-base.
As an example I’ll probably pop this comment in there later, so some of the materiel is mundane. Some of it seemed profound in the context of my life at the time, but might make less sense years later out of context.
I’ve only ever deleted a handful of entries in that 17 years.
I guess parts of it are a bit like a diary too, but I’ve never been very good at intentionally keeping a diary.
I've been doing this for years (on paper, no less) without knowing that it had a name.
Edit: Here's an article that gave me some good ideas about different things to do with my book.
Commomplace book - https://en.wikipedia.org/wiki/Commonplace_book