search engine optimization, and How PageRank Works

Posted on April 20, 2009
Filed Under Search Engine Optimization, Traffic Generation | Leave a Comment

When building a website and conducting seo, it won’t be long until you come across the term PageRank. People have obsessed about PageRank over the years, but what is it, and how exactly does it work? Being a responsible web design, and seo, company it has been our job to find out.

Google PageRank was developed in 1995 by Google creators Larry Page and Sergey Brin as a means to organize the mass of data that was forming on the Internet. In the early days of the World Wide Web websites were massed together on portals and bulletin boards and it was very difficult to find what you were looking for. Larry Page and Sergey Brin put their heads together at the Stanford University in California, USA and developed the PageRank system, which then led on to the Google search engine.

PageRank works by utilizing the linking structure that the web offers, to let the websites themselves decide what other websites are about, and how important they are. It works by counting the number of links a web page has pointed towards it by other websites. The logic is that if there are many websites pointing at a page of a single website, then that page must be pretty important. And if the anchor text, that is the words that contain the link to the page in question contain the words “blue widgets”, then logically that web page must be about blue widgets. Google the search engine would then serve up the page to anyone that is conducting a search for “blue widgets”.

PageRank is worked out on a scale of 1 to 10, with 10 being the most important. This is why in the early days of search engine optimization PageRank was considered very important for seo. A link to a website from another website which had a high PR would usually be enough to get a website on to the front page of Google. In fact it is a bit more complicated than that.

PageRank is itself a probability, so a number is always included between 1 and 0

A PageRank 1 means that a random exploration of the Google index (taking any page then following the external links) will lead to the site in 100% of the cases.

A PageRank of 0.5 means that the same will be true in 50% of any random exploration, which is already a very large number.

With 15 billions of pages in the index, any page would have a minimum PageRank of. 6,66666E-11 (or if you prefer 0,0000000000666666). All the pages in the index are sorted in ascending order on the PageRank. All the pages below a minimum are ignored and given a PR 0.

Then 90% of the first remaining pages are given a PR 1.

90% of the remaining 10% of the previous step are given a PR2

again, 90% of the remaining 10% of the previous step are given a PR3….and so on until PR10.

It means several things:

1) the more pages being added to the index, the more links you will need just to keep the same PR.

2) Within a same class of PR, different pages can have a large difference of real PageRank, and you’ll never know if a page is at the lowest limit or the highest limit of a given class. If a page is at the highest limit, just a few additional links may be needed to reach the upper PR, while another page of the same class may need thousands additional links to get to the upper PR.

Due to the way it is sorted, among the 30-40 existing PR10 pages, their real Page Rank could be 0,876543 for the highest and 0,3219876 for the lowest, which is a really huge difference, but both pages will display the PR10 green bar.

This could be developed further by considering if Google conducts explorations based on categories. It would make sense that for an exploration of the index for the key search phrase “web design” would yield around a billion results. It would then be much harder for a website that was in the category of web design to achieve a PR5, that it would be for a website in the category of “lawnmower repair”, in which there might only be around a million results.

PageRank is far less important for seo now than it used to be, but is still worth bearing in mind for seo campaigns that are aimed at competitive categories. It may be a lot harder to achieve PageRank in a competitive field, than in a non competitive field.

Just for the record this article was written by DeepSpaceDesign an innovative and ambitious web design and seo company based in the UK. Thank you for reading.

P.S. Monetize your traffic better – read these make money with adsense tips.

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