What is the PR value

PR value’s (PageRank) name comes from Google’s founders Larry Page, it is one part of google’s ranking algorithm(ranking formula) and used to identify the page Level and importance. Level is from 0-10, 10 is out, higher the PR values is, ​​more popular((more important) the website is. google give its website 10 level.
PR value formula:
PR(A) = (1-d) + d(PR(L1)/C(L1) + … + PR(Ln)/C(Ln))
Description: d is a damping factor, usually 0.85, PR (L1) indicates that the external link PR score of the site, C (L1) is the number of external links, such as there is a link to your website, its PR value is 6, the number of external links is 20, then we can calculate the PR value with this formula : PR (AnQ) = (1-0.85) +0.85 (6 / 20) = 0.45.
The relationshipPR between PR value ​​and ranking:
1, PR is high, ranking is not necessarily high, many factors affect the ranking, PR is only one factor. Google have more than 200 ranking factors.
2, But if the content and keywords match, when PR is high, ranking will be high.
Through the PR value formula, we can see that, although PR value is important, the site external link number is also a important factorof need to be considered, the level of PR value, in addition to the number and quality of external links, it also has relation with site structure, relevant inbound links. The ?Rel = “nofollow” code which controls the flow of PR value, usually located in the foot of the page.
When we are building external links in SEO, we should look for those sites of high PR value but a little external links, this site suits for our SEO.