"Basically, users’ habits on the Web aren’t that different from customers’ habits in a store. Visitors glance at each new page, scan some of the text, and click on the first link that catches their interest or vaguely resembles the thing they’re looking for. In fact, there are large parts of the page they don’t even look at.
Most users search for something interesting (or useful) and clickable; as soon as some promising candidates are found, users click. If the new page doesn’t meet users’ expectations, the Back button is clicked and the search process is continued."
[via Smashing Magazine]