What is Pagerank
Pagerank is a link analysis algorithm typical for google, but with google being by far the most used search engine it is not a bad idea to base your SEO on it. Pagerank is a complex algorithm where a weight is assigned to a link and a rank given to a page based on the weight of the backlinks that page gets. This rank spreads from 0 to 10 with 0 being a page with no important backlinks and 10 an almost unreachable rank only assigned to pages of great importance like Google and Microsoft. This algorithm is not created by Google but what Google was based on. The pagerank algorithm is created by Larry Page and Sergey Brin, creators of Google.
The pagerank of a website is calculated by adding the pagerank of the pages divided by the number of links on that page. With an example, if you want to calculate the pagerank of a page A with 3 backlinks (B,C and D) you need to look at each page’s pagerank and the links on that page, including the links to pages on the same website. So a backlink with PR4 with only 10 links has move value then a PR6 with 100 links.
Now the google pagerank theory includes the thought that a visitor will not endlessly keep on clicking on random links and eventually will stop. At every step there is a chance the person will continue, this is called the damping factor. There is no certainty how much this factor is but studies show it is somewhere around 0,85. The algorithm includes this damping factor by distracting the damping factor d from 1 (thinking the sum of all pageranks is 1) divided by the number of backlinks and adding the sum of the backlinks value times the damping factor. When a page has many backlinks the standard value of 1 will be brought down and increased with the values of the backlinks, therefor it is important to have many quality backlinks.
Google’s official statement about their pagerank is that webmaster should not focus on retrieving a high pagerank as it is not the most important metric for them to track. A high pagerank simply shows that many people have interests in your website and is interesting for online marketing.