Overview

Like most aspects of usability, navigation is invisible when it's working. But when there's a problem, users can get completely stuck. In fact, navigation problems frequently caused users to give up.

The problems we saw were primarily due to two things:

• Users did not have the domain or business area knowledge they needed to navigate the site
• The site structure didn't meet users' expectations

We also looked at some of the devices that designers used to help users traverse their sites: frames, tables of contents, and so on. (We looked at links also, and found that they deserve their own chapter. For more information, see Chapter 3.) Some of these devices helped, and some didn't. You might want to check them out before you put lots of effort into implementing them for your site.

Domain Knowledge and Navigation

Some of the sites we tested, such as Travelocity and Fidelity, assumed that users had a lot of detailed knowledge about the domain or business area covered by the site. These sites tended to finish low in our ratings because users didn't have the knowledge they needed. When users aren't familiar with the domain, they don't understand the options that are presented to them.

High-ranking sites such as Hewlett Packard and Edmund's did not assume domain knowledge. In fact, where there was possible confusion, these sites put in explicit navigational cues. Let's look at some examples.