A sitemap is a visual or text map of a website - a short list of all pages arranged in sections as they appear on the website. The sitemap is a single file and its presence could have a considerable influence on the popularity of your website, especially if you have more content. It will allow visitors to browse the pages and find what they need way quicker, that will raise the chance for them to return to the website or to show it to colleagues and friends. The sitemap is also required for search engines like google to index your site content better, which means that some pages will show up in the results for particular searches, which may not happen without a sitemap even if you have the desired site content. This is especially valid in case you modify some web pages because the sitemap informs the search engines that they need to crawl the site again to index the latest content. Having a sitemap nowadays is fundamental rather than an optional attribute for every thriving website.