The Page Rank algorithm is used in The Page Rank Citation Ranking: Bringing Order to the Web. introduced and is the most well-known ranking criterion by Google. The algorithm is named after Google co-founder Larry Page and provides a measure of the relevance of web documents based on their reputation on the Internet . This reputation is calculated based on the inbound hyperlinks. The basic idea behind this principle is to consider the evaluation of links as recommendations and is comparable to the use of citations in the literature or in scientific reports about.

The Page Rank is a concrete value, which is calculated by the following formula:

The Page Rank is therefore a value between 0 and 1 Since the algorithm is recursive nature, the actual Page Rank is determined in several iterations. The damping factor d ensures that websites that link to each other in a loop get, no endless Page Rank. For d a value of about 0.85 is recommended.

Another consideration that comes into play when the Page Rank, the so-called "random surfer". This term refers to a user who moves randomly through the Internet (navigate between different sites), and it comes from one page to another by following the links on a web page. From a certain point of the user cancels the operation and start it again on another website randomly selected. On this model, the probability that a user visits a web page about the Page Rank of this page. In The Page Rank Citation Ranking:. Bringing Order to the Web Page Rank principle is simplistic, as in the following figure. The numbers correspond to the current Page Rank of a page (the number is within the page) or the inherited Page Rank (number is the arrow).

The Page Rank principle is a very high probability even today still used to day. However, not exactly at the above-described original form. It is believed that today, rather the so-called "Reasonable Surfer" model in the U.S. Patent Ranking documents based on user behavior and / or feature data is described, is used in the calculation of Page Rank. The big difference in this model is that the user no longer navigate clicked on a link by accident, but that depends on the user's behavior on certain factors. It is, for example, more likely that a user follows a link, which has a thematic link to the website on which he finds himself. Furthermore, the placement of the links plays a role. A link in the main content (the so-called content ) of a page is likely clicked more often than a link in the footer . The following figure illustrates the different weighting of the links in the inheritance of Page Rank. Can have a maximum value of 1 in this example a link.

Another modification to the Page Rank is the introduction of the nofollow attribute. This attribute was introduced by Google in January 2005 to the increasing amount of spam comments on blogs and the upcoming sale of backlinks curb. This should for example be possible for webmasters to place an advertising link on their site without having to manipulate the Google algorithm. Links that carry the nofollow inherit neither anchor text or Page Rank.

By the end of 2009, the display Page Rank from the Google Webmaster Tools was removed and the Google employee Susan Moskwa under http://www.google.com/support/forum/p/Webmasters/thread?tid=6a1d6250e26e9e48&hl=en commented as follows :

We've been telling people for a long time thatthey shouldn't focus on Page Rank so much; many site owners seem to think it's the most important metric for them to track, Which is simply not true. Because we removed it we felt it was silly to tell people not to believe about that, but then to present them the data, indicate that they Should look at it.

The Page Rank was in the early days of the workhorse of the Google algorithm. Nowadays, however you measure it to no longer so important. Important at this point is that between the visible Page Rank (the example with the Google Toolbar can be displayed) and the Page Rank internally used must be different. The former is updated only at long intervals (the last time in January 2011 - but with the data of June, 2010 For more, see. Page Rank Back Date 2011 ) and thus represents only a snapshot, while the Page Rank internally used is constantly updated.

Finally, once the most important facts about Page Rank in brief:

The Page Rank is a measure of the degree of a link on the internet

The "visible" Page Rank represents only a snapshot

It is very likely that the Page Rank is now working after Resonable surfers instead of the random surfer model

The Google algorithm consists of over 200 factors and the Page Rank is only one of them, whose influence has steadily declined in recent years