A site map is a visual or textually organized model of a Web site's content that allows the users to navigate through the site to find the information they are looking for, just as a traditional geographical map helps people find places they are looking for in the real world. Your web site needs a site map basically for four rasons.

1) Navigation
A site map provides an organized list of links to all the pages on your Web site. If visitors get lost while browsing your site, they can always refer to your site map to see where they are and get where they would like to go. Site maps allow your visitors to navigate your Web site with ease.

2) Theme
When visitors access your site map, they will learn a lot about your Web site within a very short period of time. A well constructed site map will allow visitors to easily and efficiently grasp the “big picture” of your site.

3) Search Engine Optimization
Since a site map is a single page that contains links to every page on your Web site, it is a very effective way to help search engine spiders crawl through your site with ease (see Helping Spiders Crawl through your Web Site). Since search engines rely on links to find the main pages of your site, a site map is a great way to get every page on your site indexed by the search engines. The more pages you have indexed by the search engines, the more potential you will have to reach a greater number of prospective clients.

4) Organization
A site map enables you to easily assess the structure of your site to see where your site is strong and where it is weak. Whenever you need to add new content or new sections to your Web site, you will be able to take the existing hierarchy into consideration by glancing at your site map.