What is PageRank?

• “PageRank is [only] one of the methods Google uses to determine a page’s relevance or importance.”
  “Google uses many factors in ranking. Of these, the PageRank algorithm might be the best known.
• PageRank evaluates two things: how many links there are to a web page from other pages, and the quality of the linking sites. With PageRank, five or six high-quality links from websites such as www.cnn.com and www.nytimes.com would be valued much more highly than twice as many links from less reputable or established sites.”
• “PageRank has only ever been an approximation of the quality of a web page and has never had anything to do with the measuring of the topical relevance of a web page. Topical relevance is measured with link context and on-page factors such as keyword density, title tag, and everything else.”

How many links do you need to get a certain pagerank?

Although nobody knows the exact Google PageRank values the table below gives a fairly good representation of how many external links, of certain PageRank values, are required to achieve a certain Google PageRank.

1. PageRank is only one of numerous methods Google uses to determine a page’s relevance or importance.
2. Google interprets a link from page A to page B as a vote, by page A, for page B. Google looks not only at the sheer volume of votes; among 100 other aspects it also analyzes the page that casts the vote. However, these aspects don’t count, when PageRank is calculated.
3. PageRank is based on incoming links, but not just on the number of them - relevance and quality are important (in terms of the PageRank of sites, which link to a given site).
4. PR(A) = (1-d) + d(PR(t1)/C(t1) + … + PR(tn)/C(tn)). That’s the equation that calculates a page’s PageRank.
5. Not all links weight the same when it comes to PR.
6. If you had a web page with a PR8 and had 1 link on it, the site linked to would get a fair amount of PR value. But, if you had 100 links on that page, each individual link would only get a fraction of the value.
7. Bad incoming links don’t have impact on Page Rank.
8. Ranking popularity considers site age, backlink relevancy and backlink duration. PageRank doesn’t.
9. Content is not taken into account when PageRank is calculated.
10. PageRank does not rank web sites as a whole, but is determined for each page individually.
11. Each inbound link is important to the overall total. Except banned sites, which don’t count.
12. PageRank values don’t range from 0 to 10. PageRank is a floating-point number.
13. Each Page Rank level is progressively harder to reach. PageRank is believed to be calculated on a logarithmic scale.
14. Google calculates pages PRs permanently, but we see the update once every few months (Google Toolbar).