The Page Rank of a web page, i is formulated as PR(i) = (1 - d) + d * [ ∑{ PR(j) / L(j) }] Where, PR(j) is the page rank of pages, which are providing inbound links to page i, L(j) is the total number of outbound links, present on page j (which is often called Out Degree of a page), and d is a damping factor which values between 0 and 1 (avg o.85). Now it's clear that, page rank or quality of a page exclusively depends of number of inbound links, page rank of the linking pages and total number of outbound link of those pages. So, Free directory or paid directory, blog page, forum page or a portal page, nothing is the matter. Matter is how many inbound links you're having and what are the qualities of linking pages.