The basic principles behind the working of search engines remain the same. It is the little variations between them that make the differences in the results. The criteria for the search vary according to search engines. This is why these criteria need to be studied for the site to be optimized for more than one of them. These variations can be in different forms. Yahoo and MSN place a lot of emphasis on on-page keyword factors while Google focuses on links available on the site. Older sites are ranked better on Google, while Yahoo has no such criteria for ranking sites.
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