Sitemaps are particularly beneficial when users can't reach all areas of a website through a browseable interface. (Generally, this is when users are unable to reach certain pages or regions of a site by following links). For example, any site where certain pages are only accessible via a search form would benefit from creating a Sitemap and submitting it to search engines.

Please note that the Sitemap Protocol supplements, but does not replace, the crawl-based mechanisms that search engines already use to discover URLs. By submitting a Sitemap (or Sitemaps) to a search engine, you will help that engine's crawlers to do a better job of crawling your site.