September 26, 2005
A Google Sitemap is an XML file that uses the Sitemap protocol. This file lists URLs in your site, along with optional descriptive information about those URLs (such as when they were last updated and how often you modify them). You can create this XML file using our Sitemap Generator or a third-party tool. Google Sitemaps are intended for processing by the Google Sitemaps program.
An HTML sitemap is intended for users of your site. Generally, this type of sitemap provides links to the pages in your site, and may provide descriptions of those pages. We encourage the use of HTML sitemaps. They make it easier for users to navigate your site. Also, as we talk about in our webmaster guidelines, a clear hierarchy with text and links helps us index your site.