All good responses. I will probably keep with the green highlighter pen method, so as to not get too caught up in following a diary.Some things are worth noting though.
I think the other reason I never kept a "diary" is because Cindy Brady kept a "diary", and I didn't want to be accused of having the tendencies of a ten year old girl.
I like DZ's classification of it being a "log" much better. I can keep a "log", but not a "diary."