Google introduced the Sitemaps protocol so web developers can publish lists of links from across their site. A site map therefore is a comprehensive list of pages and links of your entire blog, or website or simply an overview of your entire blog site at a glance.
These (web pages and web links) contents may be addressed to users or to software for specific purposes. Many sites have user-visible sitemaps which present a systematic view, typically hierarchical, of the site. The main aim of a site map is to help visitors find specific pages, and can also be used by web crawlers. Alphabetically organized site maps, sometimes called site indexes, are a different approach.
For search engines and others, to crawl your site, there is a systematic format which you will have to follow while building your site map. The XML Sitemap, which lists the pages in a site, their relative importance, and how often they are updated. This is pointed to, from the robots.txt file and is typically called sitemap.xml. The procedure, format or the style your site map will use is particularly important for web sites which include pages that are not accessible through links from other pages, but only through the site’s search tools or by dynamic construction of URL’