Reading on the Web
http://www.useit.com/alertbox/9710a.html

Nielsen, Jakob
Alertbox
1997

Abstract:

People rarely read web pages word by word; instead, they scan the page, picking out individual words and sentences. In a study John Morkes and Jakob Nielsen found that 79 percent of test users always scanned any new page they came across; only 16 percent read word-by-word.