Perhaps the most successful application of this approach to date is exemplified by the Google search engine. Google assigns a measure of reputation to each Web page that matches the keywords of a search request. It then uses that measure to rank order search hits. Google’s page reputation measure is based on the number of links that point to a page, the number of links that point to the pointing page, and so on (Brin and Page 1998). The underlying assumption is
that if enough people consider a page to be important enough to place links to that page from their pages, and if the pointing pages are “reputable” themselves, then the information contained on the target page is likely to be valuable. Google’s success in returning relevant results is testimony to the promise of that approach