Initially, results lists in search engines were created based on the analysis of keywords provided by website authors. Due to the low accuracy of such answers, newer algorithms began to refer to the content on the page, and finally also to assess the quality of not only the site, but also the sites associated with it using links (in which a link to the page was placed). Algorithms used today by Google and other leading search engines take into account not only a few, but several hundred elements and are constantly modified. The rules that determine what factors determine the order in which search results are displayed are described in the "Google webmaster guidelines" document.