I've been meaning to reply to this thread since you first posted it.
I've got notes on suspension settings for different tracks... and I have also just launched a website where I chronicle my riding sessions.
I don't have a riding dairy like yours Hubbard, but I might start one. For things like reference points, racing lines and laptimes, as well as notes on what areas of my riding need the most work.
I don't know how much graphing the data. Unless you have it set up automatically, it seems like a lot of manual work that could be better spent just reviewing your notes.