Google PageRank is important in building traffic to your website for a number of reasons. Before we discuss why, here is quick heads up on how it works.
Page Rank is based on links between your site and other sites, in fact specifically between web pages, since it is links between individual pages rather than complete websites that interests Google. That is because Google lists individual pages and not domains. There is a formula that Google uses to determine the value of each link to your site, which is based on the PageRank of the web page providing the link and also the number of other links leaving that page.