Google's Algorithm or Special Sauce formulae
Many of our clients get started with optimizing their web sites using us as consultants. Initially the impact is easy to see.
Mostly this is because the site is submitted to the search engines.
After this the work gets a little more challenging. Maintaining a page ranking is not an easy task and requires many hours obtaining, creating and updating hyperlinks on other websites to your web pages and vice versa.
The PageRank Algorithm
The original PageRank algorithm was described by Lawrence Page and Sergey Brin in several publications. They are the founders of Google. It is given by
PR(A) = (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(Tn))
where
* PR(A) is the PageRank of page A,
* PR(Ti) is the PageRank of pages Ti (Total Inbound link pages) which link to page A,
* C(Ti) is the number of outbound links on page Ti and
* d is a damping factor which can be set between 0 and 1.
So, first of all, we see that PageRank does not rank web sites as a whole, but is determined for each page individually. Further, the PageRank of page A is recursively defined by the PageRanks of those pages which link to page A.
The PageRank of pages Ti which link to page A does not influence the PageRank of page A uniformly. Within the PageRank algorithm, the PageRank of a page T is always weighted by the number of outbound links C(T) on page T. This means that the more outbound links a page T has, the less will page A benefit from a link to it on page T.
The weighted PageRank of pages Ti is then added up. The outcome of this is that an additional inbound link for page A will always increase page A's PageRank.
Finally, the sum of the weighted PageRanks of all pages Ti is multiplied with a damping factor d which can be set between 0 and 1. Thereby, the extend of PageRank benefit for a page by another page linking to it is reduced.