The Page Rank of a page is the value that Google places on the importance of a web page when compared to other web pages of the same topic in their database. The scale goes from 0 to 10 and is a logarithmic value, making it much more difficult to boost a page's PR from 5 to 6 than from 4 to 5.

A Google ranking of 5 out of 10 means that the Google spiders hit the site on a daily basis. Any subjects posted on these sites will be updated in the Google database with much greater frequency than lower ranking pages. This allows any customers researching the topic at hand to come across the competitors’ pages more readily than lower ranked websites because their sites will be placed higher on the Google Search Results page.

You can find the Google Page Rank of your website by downloading the Google Tool Bar.