Google Webmaster blog just posted a article on sitemap FAQ’s. Sitemap.xml is a best way to crawl and index your site pages quickly. The pages having no direct links from main page or those difficult to find to search engine crawlers can be easily discovered by crawler bots from sitemap file.
Sitemap is a xml format file that can be placed on your sites root directory. All your site links are listed in sitemap.xml file. Sitemap format should be accepted by all search engine bots. The universal standard about sitemap.xml can be found on site sitemap.org.
Here is the summary from Google sitemap FAQ’s:
1) Sitemap.xml file can be used by search engine crawlers to discover the pages from your site.
2) The information in sitemap.xml file is: All your site urls and individual page importance. URL importance factor is a index stating the importance of the page for search engines. This is typically a factor from 0 to 1. Crawlers can better understand your site from these links from sitemap.xml file.
3) Submitting the sitemap to search engine does not mean that your site will get higher rank. It’s just a way to make search engines aware of your site links.
4) No search engine will penalize your site in terms of ranking or indexing pages for submitting a sitemap file or wrong sitemap file.
5) You can place your sitemap file anywhere on your site domain. Make sure to submit the same path in Webmaster tools. Submit sitemap to Google in Google Webmaster tools here.
6) The preferred sitemap format by search engine bots is XML format over HTML format. However submitting both format is a great idea.
7) You can avoid duplicate content penalty from search engines by giving preference to duplicate content URLs, i.e. higher preference for url that you want to be indexed for particular content page linked from different URLs.
8 ) Placing the URL at the beginning of your sitemap.xml file does not mean higher preference than URLs placed at the end of sitemap file.
9) You can submit any number of sitemap files for one domain. Make sure to create a sitemap index file in this case.
10) And last great tip: Use this sitemap generator WordPress plugin to create and submit sitemap to Google.
Submit sitemap to different search engines here:
Submit sitemap to Google: https://www.google.com/webmasters/tools/
Submit sitemap to Yahoo: http://siteexplorer.search.yahoo.com/
Submit sitemap to MSN:
Use below ping url: http://api.moreover.com/ping?u=http://www.yourdomain.com/yoursitemap.xml
Submit sitemap to ASK.com:
Use below ping url: http://submissions.ask.com/ping?sitemap=http%3A//www.yourdomain.com/sitemap.xml