The Importance of PageRank

What is PageRank?

PageRank is basically a conceptual method of using the way websites Link together to deduce their relative importance. For example, many people might link to the BBC News website, that means it is a relatively important site while Joe Bloggs’ homepage might only be linked to by a few close friends and family, which again reflects its relative importance.

How Can I Increase PageRank?

Having more people linking to your website will certainly result in the increase of your site’s PageRank but it will only increase its importance not its relevance.
There is a certain kind of calculation involved in calculating the pagerank as per follows:
Let X be the number of links on page A and Page A has a PageRank of P. There is a universal damping effect of d called damping factor. So the value of a link "i" on page A is
Ai = d.(P/X)
If a page B has n links to it, its PageRank is the sum of all the values of the links that point to it, plus 1 minus the damping factor. So the PageRank of page B is
B = (1 - d) + A1 + A2 + ... + A(n-1) + An
One can easily observe from this that pages that have thousands of links to them, even from relatively unimportant sites, are likely to build a high PageRank for themselves because there are so many link values to add together that even though each is small, as a total, they are large. And the pages that have few links need to have individually quite a large value to make a large sum total on the whole.

Why Is There A PageRank Damping Factor?

There are two reasons for adding the damping factor:

The first one being, in order to stop PageRank spiralling out of control. As more links are created around the web, the PageRank accumulates continuously and hence for the old web pages, the PageRank continues to increase while new and fresh pages would have no way of competing for importance. Therefore, the damping factor is applied to reduce the value of the links. Another being, by keeping in view the probability description of a Random Surfer. The mathematics above is often called the Random Surfer Model. It describes the probability of a surfer being on page A, and then of clicking a link to page B. The damping factor takes account of the probability that the random surfer closes his browser and starts playing Solitaire instead. It is assumed that the damping factor for PageRank is 15% damping (meaning each link is only actually worth 85% of its true value).