I too keep a journal, although I don't limit myself to write about what I read. I write about any interesting thoughts I might have at the time or about any special observations I might have made (about me or the world around me.) I might write down questions that intrigue me or even set goals for myself. I have kept a journal for several years now and I am very pleased with it. The trick is to read the journal often and think about what you've written. I suppose it's very much like image streaming, except I use a notebook instead.

Lassic