In this chapter, we will continue to look at the subject of links, but focus on the Page Rank part of the jigsaw. This is a little technical, so I have simplified it considerably. You don't need to know all the mathematics behind PR calculations, just the principles.
OK, so what is Page Rank?
Simply put, Page Rank is a measure of how important a page is. While Google created the term Page Rank, all search engines have a similar measure of page importance.
As you will know, Google Page Rank is displayed on the Google Toolbar.
If you didn’t know that, then you probably haven’t got the Google Toolbar installed on your browser. If you want to have it, you can get it from http://toolbar.google.com/
However, this display is only updated about every 3 months, so Page Ranks displayed are rarely accurate.
just because the Google Toolbar does not show YOU the accurate PR, does not mean Google don't have and use the correct PR. Google's database is constantly updated to include the very latest PR values for pages. These are then used to help rank pages accordingly. Only once every 3 months or so do we actually get an update.
You should note also that the PR value given in the toolbar is a simplified PR compared to the values held at Google. The following discussion is a simplification of how PR is calculated and passed. Exact details are not required to understand how PR can be an effective SEO tool.