Search Engine Ranking Factors
The algorithms used by Google, Yahoo!, or Bing to calculate search results can change at any time, therefore we generally avoid citing specific details regarding particular search engines and their algorithms. Search engines have been known to occasionally modify their algorithms and, as a result, turn the SERPs upside down. Examples of this include Google's Florida, BigDaddy, and Jagger updates, the Jagger updates, one of the biggest changes in google history, we will talk about latter.
Historically, search engine marketers created optimized pages for each particular search engine. This is no longer viable, because it yields duplicate content. Rankings must be achieved in all search engines using the same web pages. Furthermore, calculations such as “optimal keyword density” and “optimal page content length” for the various search engines are almost entirely obsolete. Calculations like these demonstrate a gross oversimplification of modern search engine information retrieval algorithms.
With these disclaimers out of the way, it is time to briefly discuss the most important and consistently considered factors as a quick primer for the web site developer. We group the factors that affect search engine rankings into the following general categories: