Very interesting post by Jakob Nielsen on how people scan your pages. It's what they call an "F pattern."
As an example look at:
Some comments from the article in terms of writing for the web:
- Users won't read your text thoroughly in a word-by-word manner. Exhaustive reading is rare, especially when prospective customers are conducting their initial research to compile a shortlist of vendors. Yes, some people will read more, but most won't.
- The first two paragraphs must state the most important information. There's some hope that users will actually read this material, though they'll probably read more of the first paragraph than the second.
- Start subheads, paragraphs, and bullet points with information-carrying words that users will notice when scanning down the left side of your content in the final stem of their F-behavior.
- They'll read the third word on a line much less often than the first two words.