This is an interesting pattern, that can likely be helpful for webdesigners.

In 2006, Jakob Nielsen, a longtime consultant on the design of Web pages who has been studying online reading since the 1990s, conducted an eye-tracking study of Web users. He had 232 people wear a small camera that tracked their eye movements as they read pages of text and browsed other content. Nielsen found that hardly any of the participants read online text in a methodical, line-by-line way, as they’d typically read a page of text in a book. The vast majority skimmed the text quickly, their eyes skipping down the page in a pattern that resembled, roughly, the letter F. They’d start by glancing all the way across the first two or three lines of text. Then their eyes would drop down a bit, and they’d scan about halfway across a few more lines. Finally, they’d let their eyes cursorily drift a little farther down the left-hand side of the page. This pattern of online reading was confirmed by a subsequent eye-tracking study carried out at the Software Usability Research Laboratory at Wichita State University.