XML Schema for Sitemap files. Last Modifed 2008-03-26 Container for a set of up to 50,000 document elements. This is the root element of the XML file. Container for the data needed to describe a document to crawl. REQUIRED: The location URI of a document. The URI must conform to RFC 2396 (http://www.ietf.org/rfc/rfc2396.txt). OPTIONAL: The date the document was last modified. The date must conform to the W3C DATETIME format (http://www.w3.org/TR/NOTE-datetime). Example: 2005-05-10 Lastmod may also contain a timestamp. Example: 2005-05-10T17:33:30+08:00 OPTIONAL: Indicates how frequently the content at a particular URL is likely to change. The value "always" should be used to describe documents that change each time they are accessed. The value "never" should be used to describe archived URLs. Please note that web crawlers may not necessarily crawl pages marked "always" more often. Consider this element as a friendly suggestion and not a command. OPTIONAL: The priority of a particular URL relative to other pages on the same site. The value for this element is a number between 0.0 and 1.0 where 0.0 identifies the lowest priority page(s). The default priority of a page is 0.5. Priority is used to select between pages on your site. Setting a priority of 1.0 for all URLs will not help you, as the relative priority of pages on your site is what will be considered.