I have always lived near colleges. Both community and 4 years, and as a result of that I've built up a collection of used books from thrift stores that are filled with notes and comments from 19-25yr old students.
>The guys always write cold 2 word comments or paragraph long explanations in the margins. Lots of underlining.
>The girls write 2 or 3 sentences at a time that are more of a running commentary and feel like a dialogue they're having with the text. More highlighter and it can sometimes read like a black lady in a movie theatre.