Supplemental navigation systems (shown back in Figure 7-2) include sitemaps, indexes, and guides. These are external to the basic hierarchy of a web site and provide complementary ways of finding content and completing tasks. Search also belongs to the supplemental navigation family, but is so important that we’ve dedicated all of Chapter 8 to the topic.
Supplemental navigation systems can be critical factors for ensuring usability and findability within large web sites. However, they’re often not given the care and feeding they deserve. Many site owners still labor under the misconception that if they could only get the taxonomy right, all users and all user needs would be addressed. Usability pundits feed this fantasy by preaching the gospel of simplicity: users don’t want to make choices, and resort to sitemaps, indexes, guides, and search only when the taxonomy fails them.
Both statements are theoretically true, but miss the point that the taxonomy and the embedded navigation systems will always fail for a significant percentage of users and tasks. You can count on this like death and taxes. Supplemental navigation systems provide users with an emergency backup. Do you really want to drive without a seatbelt?
In a book or magazine, the table of contents presents the top few levels of the information hierarchy. It shows the organization structure for the printed work and supports random as well as linear access to the content through the ...