A sitemap is a visual or text map of a site - a short list of all pages organized in sections as they show up on the site. The sitemap is a single file and its presence can have a substantial influence on the popularity of your website, particularly if you have a lot of content. It will permit visitors to go through the pages and find what they need much more quickly, that will increase the possibility for them to revisit the site or to show it to colleagues and friends. The sitemap is also required for search engines to index your content better, which means that some pages will show up in the results for certain searches, which might not happen without a sitemap even when you have the necessary site content. This is especially valid when you update some pages as the sitemap tells the search engines that they have to crawl the internet site again so as to index the new content. Having a sitemap these days is a necessity rather than an optional attribute for every profitable website.