How is possible that two people using the same search engine and the same query at the same time can get different results? The links below will guide you through the different ways that search engines rank results. Search Engine Ranking Factors from SEOmoz covers over 100 factors that search engines might consider to do their initial ranking. Internet marketing consultant, Bill Slawski of SEO by the Sea, outlines 20 different ways in which search engines re-rank and ‘personalize’ results, including basing rank on your previous search history, and sorting by country preferences.