Use Typography and Layout For Skimming
http://www.gooddocuments.com/techniques/typography.htm

Bricklin, Dan
Good Documents
1998

Abstract:

People know to look in border areas for navigation. They know that short, bold paragraphs on the side may be of interest, perhaps as summaries. Their eyes stop on bold words intermixed with normal. Decide which things the reader must find, and use these techniques to help them find those things.