How Circular links affect Google's Page Rank

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Google's Page Rank algorithm is not as simple as I describe in my post. I am just trying to highlight one aspect of it and how circular links are dealt with by Google.

To decide Page Rank for a page, google crawler goes through the web and sees how many times a web page is hit. More is the number of hits better will be the Page Rank. During its early days, when people discovered this algorithm, they started creating circular links i.e. A->B->A.  Once crawler reaches A, it will hit B and then back to A and so on. This helped them increase page ranks.  Google algorithm could ofcourse track small circular links and ignore them. But when the links are quite big, its not really possible to detect and eliminate them. They might eliminate a few genuine links in that case. To exploit this loophole, people started creating something called "Page farms", which are a set of unused popular links with high page ranking, you buy from the domain name owner and then use it to point a link to your website. These kind of links would then form long circular links difficult to detect at any time.  Since page rank of a page also depends on the page rank of the pages which point to this page, it helped in raising the page rank tremendously.

To counter such efforts, google came up with a  probability model. At any time when crawler reaches a page it goes to the link pointed to by this page with probability x and to some random link with probability (1-x).  So the probability of going through the circular link is reduced by (1-x) at every step. Because crawler has some randomization added which cannot be predicted and manipulated, it helps is generating a better page rank.

It is also important to note that "Page Rank" is not the only factor that determines where your Page is listed on Google. There are several more important factors to it like content relevancy. At anytime it is better to optimize your content and to advertise it through social media rather than generating circular links to increase Page Rank :)