http://booksbxfx6ciebutmfvorkotgfbwcwp24qpcxyuyen355z4eknxbzuqd.onion/dark/Smin_Oienen_-_Dark_Web_And_Deep_Web_Place_Of_Anonymity_And_Freedom_Of_Expression/DARK_WEB.html
Search engines such as Google, Yahoo or Bing index well over a billion pages on the World Wide Web, such as shopping sites, blogs, social networks, news portals, etc. Publicly available websites are searched for with the help of software called web crawlers, also known as search robots. The search robots visit the websites and follow the links published on them. In particular, the software looks for changed information, new websites and outdated links.