Google's PageRank System
The Google algorithm's most important feature is arguably the PageRank system, a patented automated process that determines where each search result appears on Google's search engine return page. Most users tend to concentrate on the first few search results, so getting a spot at the top of the list usually means more user traffic. So how does Google determine search results standings? Many people have taken a stab at figuring out the exact formula, but Google keeps the official algorithm a secret. What we do know is this:
- PageRank assigns a rank or score to every search result. The higher the page's score, the further up the search results list it will appear.
- Scores are partially determined by the number of other Web pages that link to the target page. Each link is counted as a vote for the target. The logic behind this is that pages with high quality content will be linked to more often than mediocre pages.
- Not all votes are equal. Votes from a high-ranking Web page count more than votes from low-ranking sites. You can't really boost one Web page's rank by making a bunch of empty Web sites linking back to the target page.
- The more links a Web page sends out, the more diluted its voting power becomes. In other words, if a high-ranking page links to hundreds of other pages, each individual vote won't count as much as it would if the page only linked to a few sites.
- Other factors that might affect scoring include the how long the site has been around, the strength of the domain name, how and where the keywords appear on the site and the age of the links going to and from the site. Google tends to place more value on sites that have been around for a while.
- Some people claim that Google uses a group of human testers to evaluate search returns, manually sorting through results to hand pick the best links. Google denies this and says that while it does employ a network of people to test updated search formulas, it doesn't rely on human beings to sort and rank search results.
Google's strategy works well. By focusing on the links going to and from a Web page, the search engine can organize results in a useful way. While there are a few tricks webmasters can use to improve Google standings, the best way to get a top spot is to consistently provide top quality content, which gives other people the incentive to link back to their pages.
To learn more about search engines and related topics, follow the links below.
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More Great Links
- "Google Technology." Google. http://www.google.com/technology/
- "Google's New Web Page Spider." Search Engine Promotion Help. October 5, 2004. http://www.searchenginepromotionhelp.com/m/articles/search-engine-optimization/googles-new-spider.php
- "Ranking high at Google." A Promotion Guide. http://www.apromotionguide.com/google.html
- Austin, David. "How Google Finds Your Needle in the Web's Haystack." Grand Valley State University. http://www.ams.org/featurecolumn/archive/pagerank.html
- Bereitschaft, Brad. "Getting Listed in the ODP, Google Directory." Search Engine Guide. March 23, 2005. http://www.searchengineguide.com/brad-bereitschaft/getting-listed-in-the-odp-google-directory.php
- Brin, Sergey and Page, Lawrence. "The Anatomy of a Large-Scale Hypertextual Web Search Engine." Computer Science Department, Stanford University, California. http://infolab.stanford.edu/~backrub/google.html
- Callan, David. "Google Ranking Tips." AKAMarketing.com. http://www.akamarketing.com/google-ranking-tips.html
- Collins, Gord. "The Latest on Google's Algorithm." SEO Today. April 6, 2004. http://www.seotoday.com/browse.php/category/articles/id/446/index.php
- Fishkin, Rand. "A Little Piece of the Google Algorithm - Revealed." Seomoz.org. October 16, 2006. http://www.seomoz.org/blog/a-little-piece-of-the-google-algorithm-revealed
- Fishkin, Rand. "If They Did Leak the Google Algorithm . . . " Seomoz.org. October 12, 2006. http://www.seomoz.org/blog/if-they-did-leak-the-google-algo
- Hansell, Saul. "The People Inside Google's Black Box." Bits. The New York Times. December 18, 2007. http://bits.blogs.nytimes.com/2007/12/18/the-people-inside-googles-black-box/index.html
- Kopytoff, Verne. "Google surpasses Microsoft as world's most-visited site." San Francisco Chronicle. April 25, 2007. http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2007/04/25/MNGELPF0DR1.DTL&type=tech
- Rogers, Ian. "Google Pagerank Algoirthm and How it Works." Ian Rogers. http://www.ianrogers.net/google-page-rank/
- Sobek, Markus. "The PageRank Algorithm." eFactory. http://pr.efactory.de/e-pagerank-algorithm.shtml