I am often asked about search engine rankings and what one has to do to improve those rankings. There are many factors involved and I plan to cover as many as I can over the next few weeks. In this post, I’ll be explaining the basics behind Google’s PageRank system.
What is Google PageRank (PR)?
Google has developed many ways of determining how important and relevant a website is in order to rank them in their search results accordingly. The PR system is a numeric value that Google gives to your page, on a scale of 0 to 10, with 0 being the lowest (and therefore the least important in Google’s eyes). Google then uses this value, amongst other factors, to decide how well you perform in its search results.
How is PR calculated?
The concept is simple. If a web page (A) links to another page (B), Google sees this as a vote for page B by page A, and therefore the page must carry a certain level of importance. If 1000 web pages link to page B, then this page B must be even more important.
However, it’s not just about quantity. Pages linking to page B will also be checked for relevancy and importance themselves, so quality is a very important factor. This is to deter the use of so-called “link farms”, which are just pages of links designed to boost importance of certain pages. This may have worked once, but Google have clamped down and the use of sites like this could cause your rankings to plummet, or you could even face a lifetime ban from Google.
Part of why this system works so well is by the nature that PR is passed from one page to another.
There is a fairly complex formula behind the sharing of PR between web pages, which I won’t go into now, but in basic terms it works like this;
We know that page A is linking to page B, giving it a “virtual vote of confidence”. But page A could also be linking to many other pages, so this vote for page B becomes diluted. For example, if page A has a PageRank of 5, and it is linking to 5 external web pages, then each of these pages will be assigned a fraction of this PR value of 5.
All inbound linking pages are taken into account when calculating your own PR value.
The distribution of PR also works internally within your website. If your home page has a higher PR than your inner pages, then the home page will share some of it’s PR between any internal pages it links to.
We can see from the PR system that the best way to boost your own PR is to get as many high PR websites to link to yours as possible, but these must be relevent (if you are in a band and have a website, you’d do better getting a link from a record company, rather than a pizza delivery website), and the number of other sites they link to should be as few as possible for maximum effect.
As I mentioned before, PR is just one system that Google uses to decide the importance of a website. I’ll be explaining some of the others soon.