Page Rank is Google's system for ranking websites from 0 to 10 based on the number of incoming links, with more links resulting in a higher Page Rank. While Page Rank is constantly updated, the visible ranking is only updated a few times a year. Sites listed in the Google directory can provide a more current estimate of Page Rank, as it lists sites in order of their current ranking. However, Page Rank alone does not impact search engine results or business metrics like traffic or sales. It can help with link exchanges and pricing links for sale on a site, with higher Page Ranks commanding better deals.