Poorly Designed Web Navigation

You will lose a great deal of visitors through poor web site navigation. When we are looking for something on a web site our attention span decreases and if something is too hard to work out, visitors will just hit the back button. Put yourself in your visitors position, how long do you stay on a web site that makes no sense, maybe 5 or 10 seconds, about as long as it takes to hit the back button.

The important thing to remember with navigation is to keep it consistent.
You will notice on this website that the main navigation on the left always stays the same, it never changes and all of the buttons point to the same place no matter what page you are on.
This allows the visitor to become comfortable and familiar a lot quicker than if the main navigation was to change on every single page.

In summary the object is to make sure its very difficult for the visitor to get lost on your page. If they do get lost then you should make sure you have a site map available on every single page so that the visitor can easily recover and continue enjoying your web site.