Google Sitemaps is an easy way for you to help improve your coverage in the Google index. It's a collaborative crawling system that enables you to communicate directly with Google to keep us informed of all your web pages, and when you make changes to these pages. Google is the number one search engine and they have very good webmaster tools that allow you to submit your site map so they will know about it. They also have options that let you see if your website is in their website database and if the Google robot found any errors in your website (unreachable pages, etc). Google likes them and uses them to index your site and help create a relevant search experience for your site visitors.

Creating and submitting a Sitemap helps make sure that Google knows about all the pages on your site, including URLs that may not be discoverable by Google's normal crawling process. We use the data in your Sitemap to learn about your site's structure, which will allow us to improve our crawler schedule and do a better job crawling your site in the future.

Sitemaps are navigational helpers provided on a website to help ensure efficient crawling of their pages by the search engines. They help in providing information to the crawlers about the pages in a website, and their file structure. Sitemaps are particularly useful to be used with blogs that have dynamic content. See the About Sitemaps help topic on GWT help center for more information on them. Sitemap index files may not list more than 50,000 Sitemaps and must be no larger than 10MB (10,485,760 bytes) and can be compressed. You can have more than one Sitemap index file.

Web crawlers usually discover pages from links within the site and from other sites. Sitemaps supplement this data to allow crawlers that support Sitemaps to pick up all URLs in the Sitemap and learn about those URLs using the associated metadata. WebUpon describes it as "A Sitemap is a graphical representation of the architecture of a website. There are two kinds of site maps. Web page creation is no child's play. A huge amount of time is spent in planning the look and feel of a website, before the actually development begins.

Webmasters themselves have begun to see the benefits that this file provides. Search engines rank a page according to the relevance of its content to particular key words-but until the XML format, there were instances when that content was not properly picked up. Webmasters usually benefit from submitting sitemaps and will not be penalized for it.