Building Link Popularity
What is "link popularity"?
Link popularity relates the number and quality of incoming links that point your site. Building link popularity is one of the difficult areas of SEO. It is because engines do not want artificially created links and that makes building link difficult. This is the reason building link popularity is one of the difficult and time consuming practice of SEO,
you are pointing about Page Rank right? well PR is based on the volume of quality links you are earning.. at some point , on the traffic you are generating as well... For me SERP is more time consuming than PR...actually im not prioritizing my PR..SERP is far more important....