Sitemaps
What Are Sitemaps?
Sitemaps or site map are used so search engines can do a better job of crawling your website. Sitemaps provide valuable information for webmasters to inform search engines about 
pages that are available for crawling. Sitemaps can include metadata about each URL. This information includes how important it is relative to other URLs on that website, when it was last updated, and how often it usually changes. The most popular type of sitemap is a xml sitemap, which users don't see but provides informaiton to search engines.
It is common for people to discover pages from other websites or links within your website. Sitemaps pick up and learn about all URLs using metadata. Sitemaps are not necessary but allow web crawlers to discover most of your site through the search engine they are coming from.
Sitemaps are particularly beneficial if your website meets one of the following criteria:
- Large archive of isolated content pages or not well linked to each other.
- Your site is either new and has few external links or very large.
- Your site heavily uses media content, shown in Google News, or use other annotations that are compatible with Sitemaps.
Are Sitemaps Necessary?
Sitemaps are not necessary. However, they will improve crawling if it meets one of the following criteria:
- Your website is new with few external links.
- Your website contains a lot of media, uses annotations compatible to Sitemaps, or is shown in Google News.
- Your website is large.
- Your website has an abundance of content pages that are not well linked to each other or are isolated.
To learn about Sitemap Protocol and Sitemap Index Files, visit the link below:
http://www.sitemaps.org/protocol.html
