A sitemap provides search engine spiders with information about all of the content available on a site, and allows them to access every specified page without crawling the site links.
Ensuring that site content is included in Web search indices, such as Google and Yahoo, is important in raising a site's search ranking. A sitemap serves as a starting point that ensures that important locations in your application are possible for crawlers to locate, and are properly ranked.
Additionally, pages within commerce applications aren't typically linked by outside sites. Listing a set of representative product pages in your sitemap helps present an accurate portrayal of your application, which leads to more hits when users enter a relevant search query.
The Sitemap Generator creates files that use the XML Sitemap protocol, which Google, Yahoo!, Microsoft, and Ask.com have agreed to support. You can find out more about sitemaps and the sitemap protocol at http://www.sitemaps.org.
