Page Rank

PageRank is a form of link analysis, developed by Larry Page and Sergey Brin. A subset of network analysis, whereby many associations between objects are taken into account. The associations between a great deal of objects are not always apparent from isolated pieces of information. Fully automatic, computer-based link analysis is what is used by telecommunication operators for telecommunication network analysis. It is also used by banks, the medical sector, law enforcement and in this case, search engines. This technique is implemented in order to deliver an appropriate relevance rating. Conversely this technique is also used by spammers for something known as Spamdexing (search spam or search engine spam). The process of modifying HTML pages to increase the chance of a page one hit.

The success of Google, rising to dominance over it's competitors in the late 90's, was largely attributable to the implementation of PageRank. Since the use of PageRank, Google has remained largely unaffected by Spamdexing but has not been immune to more evolved techniques such as Google Bombing. This process is also known as a 'link-bomb' or 'Googlewashing', where, in an attempt to raise the rank of a given page, sites would be created with keyword links to the page that black-hat optimisers wanted to bomb. This is usually done with a political or humorous motivation. For instance the 1999 Google bomb that returned the Microsoft Homepage for the keywords “more evil than Satan himself”. Since January 2007 this technique has been largely ineffective. However Google is not without a sense of humour itself, with the first result for the term “find Chuck Norris” returning this page.

What PageRank does exactly is to assign a numerical value to each element of the world wide web with the intention of measuring its relative importance. In a Google description of page rank they say:

“PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page's value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyses the page that casts the vote. Votes cast by pages that are themselves "important" weigh more heavily and help to make other pages "important".

In other words, the page rank of a given page is derived from the numeric value of that page in the eyes of Google as well as the values of the pages that link to it. Thus making link farming and other methods of Spamdexing obsolete. The purpose of this is to engender meaningful web pages over the garbage that started to clutter up the other search engines before Google came on the scene.

Although Google provides no specific details about the other factors which influence page rank in the hopes of maintaining the integrity of the algorithm, in practice it has proven to be vulnerable to manipulation and much time and effort has been spent on researching a way to minimize page rank that has been inflated in a false manner.

Understanding PageRank is necessary for any SEO operation you want to undertake, be it for a service you are providing or for your homepage. It is essential to keep up to date with this dialogue since the rules are constantly shifting, you need to move with them or risk, at best, decreasing the value of your page in search engine results or at worst, becoming liable for inflicting a negative page rank on somebody else.