PR stands for Public Relations. It also stands for Proportional Representation. But in the world of internet marketing, PR means PageRank. And it is the key to successful exploitation of the internet.

So what is it and what does it do? First the technical bit:

The PageRank algorithm (a sequence of instructions, basically) was originally created at Stanford University by Larry Page hence it is called PageRank, or at least that’s what it says in The Google Story, by David Vise and Mark Malseed (2005).

What is it for?

Google assigns to your web page an importance in the form of a numeric representation (from 0 to 10), 10 being the highest value. There are not many PR10 sites, but here is a list of some of them from which you’ll see that a PR10 site is pretty important.

Adobe - http://www.adobe.com/

World Wide Web Consortium - http://www.w3.org/

Google Search http://www.google.com

National Science Foundation - http://www.nsf.gov

The White House - http://www.whitehouse.gov

US Government website - http://www.usa.gov/

So the real question is how does it work? Well in simple terms Google thinks that when one page links to another page, it is casting a "vote" for that other page. The more "votes" a page has, the more important the page.

What makes it more interesting is that not all "voters" are equal. The importance of the page that's casting the vote determines how important the vote itself is. So the higher the PR of the page that's casting the vote, the more that vote is worth to your page.

It’s a bit like The X Factor on TV: A vote from Simon Cowell carries a lot more weight in the music business than a vote from Cheryl Cole.

Below is a more technical explanation for those of you who are that way inclined. If you’re not, skip on a paragraph or two!

Page Rank Example

Welcome back to the non-tech world, dear readers.

Simply put, the more links a page has going out the less valuable those links become to the site they are linking to. So if you have one link going from a PageRank 3 page to your website that is a good link.

If you had a link to your site from a PageRank 8 page, but there are 100 other links from this page, you would be sharing the link value of that page with 100 other sites meaning the PR3 page would actually be a better vote for your site. Where as the more links you have coming into a page, the higher that page’s PageRank will become.

PageRank is also affected by the internal linking structure of your website. This works very much like the external links calculation above. Each internal page has a PageRank that can be used to vote for other pages on your website.

So as you can see, link strategies can be quite complex. Another factor in this scenario is that the more pages you have on a site the more pages that can vote for other internal pages. So the more pages you have, the higher your site’s PageRank can become.

Outbound links from your page leak PageRank. There are a few ways of stopping this from happening. The best way is to use the rel=”nofollow” attribute e.g. link text. This will tell Google not to pass any of your page’s rank to the linked page.

Google will still actually follow the link and if the page it is linked to it in Google’s directory, it will still reindex the page. This attribute is commonly used on Blog sites to stop spam blogging (where people post blogs or entries on forums, guest books, wikis etc. with links to commercially promote their site and help generate additional PR for their site.)

In summary:

PageRank is Google's way of deciding how important your website is. 0 is the lowest PageRank, while 10 is the highest. A higher PageRank can seriously affect your search engine position.

The more links from high PageRank pages your site has, the greater its importance in Google. The more links internally to your pages, the more important certain pages on your site will be.