How Your Visitors Behave
Understanding your visitors' actions is important to helping you develop a better understanding of what they are looking for. It can provide an insight into their experience while on your site and can indicate methods to offer improved web design or web development in order to enhance their enjoyment and improve your results.
When a visitor lands on your website, whether it be through the search engine results or via any other source of traffic, they will skim your website as long as they aren't overly hampered by slow loading pages (a vital part of web development in itself). They will get a general feel of the site by initially and quickly viewing what is immediately available to them.
As such, the most important part of a website is the section that is above the fold. The fold is the section of the website where visitors must scroll in order to see more information. When considering your own web development you should deliver the main message of a page so that it appears above this position.
A large part of web development is about identifying visitors' needs and then striving to meet them. By bowing to the whim of your visitors you can help to ensure the success of your website. Also remember that the browser's back button is one of the most widely used buttons and visitors will use this as another means of navigation so the top left of the page is the area that will get the most attention – make the most of it.