Google refreshed/updated its toolbar Pagerank in the first week of August. Although this year has been dominated with the Panda and Penguin turmoil ever since the last pagerank update in Feb (and subsequently in May), a pagerank update is still awaited by many as a high PR or any increase in pagerank gives bragging rights to the webmaster. This blog of mine finally got its PR of 1 after being active for a little less than 5 months.
What Is The Pagerank?
Pagerank is an algorithm named after Larry Page (co-founder of Google, hence Page-Rank) which assigns a numeric value depicting the importance of a page on the web. It is generally referred to as PR (and no, it doesn’t mean public relations).
Importance of a page is determined by the links to that page. A link from page A to page B is effectively seen as a vote by page A for page B. The PR algorithm understands that more votes cast for the page mean that the page is important. It also takes into account the importance of the pages casting the vote. A combination of these factors helps decide the pagerank for a particular page and website.
According to Google;
PageRank reflects our view of the importance of web pages by considering more than 500 million variables and 2 billion terms. Pages that we believe are important pages receive a higher PageRank and are more likely to appear at the top of the search results.
PageRank also considers the importance of each page that casts a vote, as votes from some pages are considered to have greater value, thus giving the linked page greater value. We have always taken a pragmatic approach to help improve search quality and create useful products, and our technology uses the collective intelligence of the web to determine a page’s importance.
How Is The Pagerank Calculated?
The Google Pagerank is effectively an algorithm, and follows a set of equations. I can explain (or try to) how this works.
Lets start up with a web which has only 4 pages- A, B, C and D. While doing our calculations, we keep in mind that a link from a page to itself or a link to another page multiple times from any page are ignored.
- Assuming that all pages have the same PR to start with, we can assume that each page possesses a PR of 0.25.
- The PR of a page is divided equally among all its outbound links. So if we can assume that pages B, C and D link out to A, then they all pass 0.25PR to A. Hence:
PR(A)=PR(B)+PR(C)+PR(D), i.e, a total of 0.75.
- However, if page B links out to A, C and D, and page C links out to page A and D and page D links out to only page A, the equation is revised as:
PR(A)=[PR(B)/3]+[PR(C)/2]+PR(D), i.e, now page B passes PR of ~0.08, page C passes PR of ~0.12 and page D passes PR of 0.25, for a total of 0.378.
Hence we can say that pagerank passed by a page is equal to its own PR divided by number of outbound links. The total PR received by a page can hence be calculated as the sum of all the PR given by individual pages, i.e,
PR(X)= summation of [PR(Y)/L(Y)] with Y is contained in the set that has all links to page X. Hence, the page rank of a page X is dependent on the PR values of each page Y contained in the set which has all links to page X, divided by number of outbound links from page Y. This is the simpler part. For all you maths geeks out there, find the full calculations here.
Factors Affecting Pagerank
There are a few factors which can affect how the pagerank increases or decreases across your website. Find Out The Factors By Clicking Here