Eye tracking studies involve using cameras and pattern recognition to track where the user's eye travels on a web page.  They can then take this camera data and create heat map overlays of the web page and get an accurate measurement of what really draws the users attention.

Here are 20+ lessons learned from a recent study.

• Ads in the top and left portions of a page will receive the most eye fixation.
• Ads placed next to the best content are seen more often.
• Bigger images get more attention.
• Clean, clear faces in images attract more eye fixation.
• Fancy formatting and fonts are ignored.
• Formatting can draw attention.
• Headings draw the eye.
• Initial eye movement focuses on the upper left corner of the page.
• Large blocks of text are avoided.
• Lists hold reader attention longer.
• Navigation tools work better when placed at the top of the page.
• One-column formats perform better in eye-fixation than multi-column formats.
• People generally scan lower portions of the page.
• Readers ignore banners.
• Shorter paragraphs perform better than long ones.
• Show numbers as numerals.
• Text ads were viewed mostly intently of all types tested.
• Text attracts attention before graphics.
• Type size influences viewing behavior.
• Users initially look at the top left and upper portion of the page before moving down and to the right.
• Users only look at a sub headline if it interests them.
• Users spend a lot of time looking at buttons and menus.
• White space is good.

Found from Seth Godin based on Tim's study