The PageRank

The name PageRank, which is a trademark from Google, is a pun between Page Rank, rank of a page, and Larry Page, one of the two founders of the company, which owes his initial success with the implementation of an algorithm with the same name. This one classifies Web pages according to their popularity on the Web, therefore according to the number of link toward them.

It is about the algorithm described by Larry Page and Sergey Brin and which is at the origin of Google.
Better PageRank will be obtained by a page with a greater number of links pointing on it but according also to PageRank these pages themselves have. If a page points on several others, the value which it brings is divided by the number of links. But the value which is acquired by links of quality being integrated into the page, it will be transmitted to the pages on which point this page.

In the act of page ranking, PageRank intervenes in a second time: in answer to a query, pages are selected according to keywords they contain. Then the pages which contain the same keywords are classified according to a whole of criteria among which PageRank.
Thus it is possible to reach the top of the results with a null PR, as soon as one is alone to evoke certain keywords. On the other hand,on competing searches, PR is a crucial factor to reach the top.

The PR has also a role in the way a site is crawled:

"The number of pages that we crawl is roughly proportional to your PageRank."
Matt Cutts.

We do not know whether this factor is relevant in 2014 as it now depends on other factors, the value given by Panda, the size of the site.

To know your PageRank, take in mind that it depends upon a group of keywords. To know the real ranking, perform searches with various keywords. The position of your page (when several match the request) gives the ranking: the top of list means for a ranking of 10. First page of search results means for 6-9 PR when lot of matches exists.

How is calculated the PageRank?

PageRank, or website ranking, is a notation from 0 to 10, given by Google to each page of a website. The higher is this value, the better will be the position of the page in results of searches, among other pages that match the request.
A 5 points PageRank is Good. 7 points may be reached with valuable backlinks. The number of 10 points PageRank websites is very short!
The word PageRank comes both from "page ranking" and "Page" that is the name of one of the two authors of the algorithm (Serguey Brin and Larry Page).

PageRank does not depend on page content but links pointing to it (and outbound links to a lesser degree).
The authors of the algorithm, from the links between all the web pages, establish a chain of Markhov which gives the probability of reaching a given page in the shortest time possible.
To be simple, to get a higher PR, you must have many links pointing to your site, and mainly quality links from sites that then themselves have many quality links pointing to them.
The "vote" of a page is transitive, if A links to B , it enhances the importance of B, and therefore, if B links to other pages, it also enhances their importance.
Moreover, if a page points to several links, the weight it brings is divided by the number of links (including nofollow links that are discounted here).
Links between pages within a site are taken into account, and they tend to transfer the PageRank from a page to another.
Reference: "Deeper inside PageRank" by A.N. Langville et C.D. Meyer.

Improving the PageRank

There are however honest techniques to increase the PR of a site! One calls that "white hat" SEO or search engine optimization. The best way is to improve the quality of your pages, their originality, but also to review their design.

Bad practices to avoid

These artifices are generally detected automatically by Google or through request from competitor who denounce sites using such tricks. The sites using the so called "black hat" SEO can be placed on a blacklist and removed from the index.

More information