A sitemap is a visual or text map of a site - an index of all pages grouped in sections as they show up on the site. The sitemap is a single file and its presence may have a crucial impact on the popularity of your site, especially when you have a lot of content. It will make it possible for visitors to browse through the web pages and find what they need quicker, which will raise the possibility for them to come back to the website or to share it with colleagues and friends. The sitemap is also required for search engines to index your content better, so some pages will show up in the results for certain searches, which will most likely not happen without a sitemap even if you have the needed website content. This is especially valid when you modify some pages since the sitemap informs the search engines that they need to crawl this Internet site again in order to index the new content. Having a sitemap nowadays is essential rather than an optional feature for any successful site.