A sitemap is a structured representation of all pages of a website. Both the site structure and the individual links between the pages can be listed. Two different sitemap types can be distinguished, HTML sitemaps and XML sitemaps.
HTML sitemaps can be used on websites as a list of all sub-pages of a website. Usually, the sitemap is filed on a separate subpage visible to all users. This sitemap is intended for users, who can be oriented based on the navigation tree just like on an actual map. Therefore, HTML sitemaps often look like the completely unfolded menu of that page. If the user clicks on a link to the site map, they will get sent directly to the linked subpage.
A Google sitemap provides search engines a clearly structured overview of existing pages on the website. The search engines have the option to more easily crawl the content through the structured data. Moreover, search engines can also specify types of pages based on the meta-data such as news, images and video content. A separate video sitemap may also get created specifically for the video content.
An XML sitemap can provide the following advantages for the site owner:
Submitting a sitemap, does not give any guarantee that the listed webpages will actually get indexed. It is merely an indication to the Googlebot that new webpages are available to be crawled.
Using the Sitemap, webmasters and SEOs can influence the crawling process for the website under their care. It is therefore a part of technical SEO. This operation will not be visible to users because it is executed in the backend. In contrast, the HTML sitemap is visible on the site. For a long time, this type of sitemap was used to strengthen the internal linking. The link to the sitemap was therefore usually placed on the homepage, so that the robot could follow these links and at the same time link juice was distributed to the subpages. Moreover, this navigation structure mainly served as an orientation for users, as easy to use menus on websites were not yet common. Today, it is questionable whether the HTML sitemap has an important influence on on-page optimization. It is more so a relic from the early days of the Internet. The real purpose of providing an overview is also rapidly lost for larger websites. Integrated search capabilities and a flat menu structure can completely replace the HTML sitemap as a user guidance tool.