Search engines spiders use sitemaps to find and index the content of websites. Basically, a sitemap is a guide that show search engines a list of pages available for indexing.
It is important to understand that a sitemap is just a guide for search engines, and not a list of commands.
The sitemap XML format is supported by many search engines including Google, Yahoo, and MSN. You can find a description of the XML schema for the sitemaps protocol on sitemaps.org.
Here is an example of an XML sitemap.
You can find descriptions of XML tags on sitemaps.org.
I just want to focus on two optional tags:
changefreq – This tag tells search engines how often you usually update the page. Please note that you just provide information about update frequency. It does not mean that search engines will index the page with the same frequency.
priority – This tag shows spiders priority of the page relative to other pages on the website. Basically, you tell search engines that pages with higher priority have more important information. It helps search engines prioritize the indexing process. Giving high priority to all pages will not help because all pages will have the same priority. And you should understand that the priority tag does not affect ranking position in search engine results pages.
Steps below describe how to create and submit XML sitemap.
1. Create the XML sitemap. You can use different automated tools listed on this page: http://code.google.com/sm_thirdparty.html.
Please note that different subdomains should have their own sitemaps located in these subdomains.
2. Put the new XML sitemap on your website. Usually, it is located in the root of the website like http://www.example.com/sitemap.xml.
Sitemaps for subdomains are usually located in subdomains like http://subdomain.example.com/subdomain_sitemap.xml
3. Submit the XML sitemap to Google in Google Webmaster Tools – http://google.com/webmasters/tools/siteoverview.
Please note that you need a Google Account to provide this submission.
4. Update (or create) a robots.txt file to include reference to the XML sitemap.
Basically, you have to add just one line in the robots.txt file like
For example, after update robots.txt file will look like
XML sitemaps provides valuable information to search engine spiders and should be used for successful search engine optimization.