Sitemaps and Site Indexes: What They Are and Why You Should Have Them
“Sitemaps and site indexes are forms of supplemental navigation. They give users a way to navigate a site without having to use the global navigation. By providing a way to visualize and understand the layout and structure of the site, a sitemap can help a lost or confused user find her way. Sitemaps are more widely implemented than site indexes, but both have their place and fulfill a unique information need.” (Chiara Fox – Boxes and Arrows)