History of Sitemap, Sitemap Format

History of Sitemap, Importance of Sitemap, Sitemap Format, Sitemap Submission Search Engines
Sitemaps protocol gives a information to search engines about URLs that are available for crawling. A Sitemap is a format of XML file and save as .xml. Sitemap file contain the list of URLs for a website. Sitemap allows webmasters to include information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs in the site.
History of Sitemap:

• Google first introduced Sitemaps 0.84 in June 2005 so any one can publish lists of urls.

• Google, MSN and Yahoo announced joint support for the Sitemaps protocol in November 2006. The schema version was changed to "Sitemap 0.90", but no other changes were made.

• In April 2007 - Ask.com and IBM announced support for Sitemaps. Also, Google, Yahoo, MS announced auto-discovery for sitemaps through robots.txt.

• In May 2007 - the state governments of Arizona, California, Utah and Virginia announced they would use Sitemaps on their web sites.

Sitemap Format:
The Sitemap Protocol format consists of XML tags. The file itself must be UTF-8 encoded.
Sample
<?xml version='1.0' encoding='UTF-8'?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
<url>
<loc> http://online-seo-information.blogspot.com/</loc>
<lastmod>2006-11-18</lastmod>
<changefreq>daily</changefreq>
<priority>0.8</priority>
</url>
</urlset>
The following table lists the Sitemap submission URLs for several major search engines:

Search engine	Submission URL	Help page
Google	http://www.google.com/webmasters/tools/ping?sitemap=	How do I resubmit my Sitemap once it has changed?
Yahoo!	http://search.yahooapis.com/SiteExplorerService/V1/updateNotification?appid=SitemapWriter&url= http://search.yahooapis.com/SiteExplorerService/V1/ping?sitemap=	Does Yahoo! support Sitemaps?
Ask.com	http://submissions.ask.com/ping?sitemap=	Q: Does Ask.com support sitemaps?
Live Search	http://webmaster.live.com/ping.aspx?siteMap=	Webmaster Tools (beta)
Yandex	—	Sitemaps files

Sitemap limits:
Sitemap files have a limit of 50,000 URLs and 10 megabytes per sitemap. Sitemaps can be compressed using gzip format. Multiple sitemap files are supported, with a Sitemap index file serving as an entry point for a total of 1000 sitemaps.