1. How do search engines work?

Search engines such as Google or Bing use software tools and are made up of three components:

• The – robot, also known as a crawler or spider – crawls the web from link to link, retrieving information (text and multimedia) from the web pages it encounters. The robot regularly returns to indexed pages to take account of any content modifications.

• An index, containing words in all languages and on all pages retrieved by the robot, links them to the URLs of the pages from which they originate.

• The web interface allows the user to launch a word query on the – engine index, with more or less sophisticated possibilities – and displays the results, sorted by relevance.

This means that when you launch a search on Google – or any other search engine...