Rule #8 - Provide redundant navigation

People learn in different ways. People behave in different ways. People's perceptions respond to different cues. So be good to everyone, and provide navigation that works in multiple ways.

This is one of the arguments for using both image maps and text. Some people are going to use the text links, even if they are loading graphics and the image map is right there on their screen.

There are other ways to provide useful redundancy, including horizontal linkage between pages at the same level in the same area (this can be either a complete mapping or threading, as appropriate), vertical linking (especially upward to all levels), including pages in more than one subject area when appropriate, putting cross-links in context within articles where it is appropriate, and for large sites, a site map page whose only purpose is to link to every page in the site in some organized manner. For site maps, it helps if every page links back to the site map as well. For the primary navigational links which provide structure to your site, be as consistent as possible about the placement of these links.

The "three-click rule" is important in navigation. It should be possible to get from any page in your site to any other page in your site with no more than three links. It's even better if there are multiple three-links-or-less paths, because different readers will try different paths between the same pair of pages.