The Google crawler then uses this map to improve coverage of your content. according to the specific information you provide about page locations, modification frequency, and more.
 
What is a Google XML Sitemap?
In short a Google XML Sitemap allows webmasters to submit a master list of your r website's pages to Google for indexing. This information is stored in an XML file along with other relevant information where specified by the webmaster. It can be as simple as a list of URL's belonging to the site, or can include, last modified date, update frequency, and priority. The purpose of this Sitemap is to have the most recent version of your URL's indexed in Google at all times.
  
Participation is free. Inclusion isn't guaranteed, but Google's say the new system will help it better gather pages than traditional crawling alone allows. Feeds also let site owners indicate how often pages change and other information.
  
The goal of google sitemaps is to provide website owners with a method of getting more pages in Google's index and notifying Google of updates as soon as they occur. Webmasters like GCWWeb Services create XML files containing the URLs which they want Google to crawl, along with optional hints about the URLs such as things like when the page last changed, and the rate of change. The Sitemap is hosted in your webspace and we tell google where it is.
 
Sitemaps helps both new and existing websites improve their Google presence. It can help newly designed websites to get more extensive crawls when Googlebot visits, and large sites with lots of web pages should see deeper crawls and speedier page discovery by showing Googlebot the layout of their site.
 
Google has for a long time depended on external links from pages they already know about in order to find new websites this new google tool will not only assist them - it will also be to your advantage if your site is afforded the google sitemap enabling Google to keep upto date speedily with your website changes..
  
As the internet gets bigger every second of every day, the problem for search engines and webmasters is becoming evidently greater. For the search engines it's taking their search spiders longer to crawl the web for new sites or updates to existing ones.
  
Who needs a Google XML Sitemap?
XML sitemaps can help any site needing to be indexed by Google. It is best used when trying to keep the latest versions of your pages current in Google. Large sites with an extensive list of URL's will benefit, especially if 100% of their pages are not appearing in the Google index. So particularly if you have either a dynamic or large site, Google XML Sitemaps will benefit you


The benefits to be gained from having a Google Sitemap created

	Enables Google to quickly find and index your website pages. Get your website indexed fast!
	Helps Google to keep search content fresh, so people have the most up to date information available.
	Speeds up the discovery of additional or new web pages on your existing website whichshould get indexed by Google faster.
	Improve your Google rankings. Using a google sitemap means that Google gets to know about your website information speedier. If you are placing new product ranges on your website - you want Google to crawl your new web pages as soon as possible. The sooner the Google crawler spiders your new web pages the better. Google can then evaluate your webpages ready for indexing in relation to the various keywords etc.
	Will become the Standard - it is very likely that soon sitemaps will become the standard way of submitting a web site to search engines.
	Change Frequency - Google allows you to tell it how often the content of a page is likely to change. If you are continually adding new product data etc - this can be of great advantage.