Site maps are becoming more popular as methods of navigating through a Web site. A site map is simply a list of links to HTML files in your Web project.

HTML sitemap is a page listing the pages of your site – often by section – and is meant to help users find the information they need.

XML Sitemaps – usually called Sitemaps, with a capital S – are a way for you to give Google information about your site. This is the type of Sitemap we’ll be discussing in this article.

In its simplest terms, a Sitemap is a list of the pages on your websites. Creating and submitting a Sitemap helps make sure that Search Engines (SE) knows about all the pages on your site, including URL’s that may not be discoverable by SE’s normal crawling process.

More about website site map and on information on  "What is "Preview Before Visit" (PBV) visit:
How to create a site map?

Good site map practice.

• Make sitemap as simplest page on your web site. Do not give a fancy name to the site map link such as “Site Navigation Tree” – keep it as “Site map”, this way your visitors understand immediately what you mean.
• Avoid “dynamic” site maps. Those in which the visitors have to “work” their way to get hold of information. Remember, the reason visitors comes to a site map page is because they are lost. To make them work again for something that you can display as a simple static link will just kill the purpose of having a site map.
• If the site map is list of <!––> text links be sure to use the TITLE attribute of the anchor tag and include keywords inside it.
• It is a good idea to put a sentence describing the page contents below the link for that page on a site map.
• A site map should not be the primary navigation on your web site it should complement it.
• A link to the site map page is very important and all pages should carry this link. The site map link can be included with other links in the main menu on your web site or placed at a section on the web page
  

  from which is it clearly visible.

• Other important aspects on a web site should complement site maps. For example, the link color for visited links should be different from that of non-visited links so that visitors understand which pages they have already seen and thus, save time.

More about website site map and on information on  "What is "Preview Before Visit" (PBV)? visit:
 How to create a site map?