Dumb SEO Questions

(Entry was posted by Tarun Wadhwani on this post in the Dumb SEO Questions community on Facebook, Tuesday, December 1, 2015).

Pagerank Algorithm

can anyone please explain me this in simple way with example?

Question=
Simplified algorithm
Assume a small universe of four web pages: A, B, C and D. Links from a page to itself, or multiple outbound links from one single page to another single page, are ignored. PageRank is initialized to the same value for all pages. In the original form of PageRank, the sum of PageRank over all pages was the total number of pages on the web at that time, so each page in this example would have an initial value of 1. However, later versions of PageRank, and the remainder of this section, assume a probability distribution between 0 and 1. Hence the initial value for each page is 0.25.

The PageRank transferred from a given page to the targets of its outbound links upon the next iteration is divided equally among all outbound links.

If the only links in the system were from pages B, C, and D to A, each link would transfer 0.25 PageRank to A upon the next iteration, for a total of 0.75.

PR(A)= PR(B) + PR(C) + PR(D).\,
Suppose instead that page B had a link to pages C and A, page C had a link to page A, and page D had links to all three pages. Thus, upon the first iteration, page B would transfer half of its existing value, or 0.125, to page A and the other half, or 0.125, to page C. Page C would transfer all of its existing value, 0.25, to the only page it links to, A. Since D had three outbound links, it would transfer one third of its existing value, or approximately 0.083, to A. At the completion of this iteration, page A will have a PageRank of 0.458.

PR(A)= \frac{PR(B)}{2}+ \frac{PR(C)}{1}+ \frac{PR(D)}{3}.\,
In other words, the PageRank conferred by an outbound link is equal to the document`s own PageRank score divided by the number of outbound links L( ).

PR(A)= \frac{PR(B)}{L(B)}+ \frac{PR(C)}{L(C)}+ \frac{PR(D)}{L(D)}. \,
In the general case, the PageRank value for any page u can be expressed as:

PR(u) = \sum_{v \in B_u} \frac{PR(v)}{L(v)},
i.e. the PageRank value for a page u is dependent on the PageRank values for each page v contained in the set Bu (the set containing all pages linking to page u), divided by the number L(v) of links from page v.

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OUR ANSWERS

Answers from the Dumb SEO Questions Panelists.

  • Micah Fisher Kirshner: Use these examples for simplification:
    http://i.stack.imgur.com/egixC.png
    https://upload.wikimedia.org/wikipedia/commons/6/69/PageRank-hi-res.png
    https://moz.com/blog/google-maybe-changes-how-the-pagerank-algorithm-handles-nofollow
YOUR ANSWERS

Selected answers from the Dumb SEO Questions G+ community.

  • Tarun Wadhwani: thanks everyone who try to give me a answer about my question. But reason behind to ask this question is wikipedia , because i see this stuff on wikipedia and I didn`t understand properly thats why, LInk where i seen this : https://en.wikipedia.org/wiki/PageRank thanks everyone once again for there time and response.
  • Tarun Wadhwani: can anyone please explain me this in simple way with example?

    Question=
    Simplified algorithm
    Assume a small universe of four web pages: A, B, C and D. Links from a page to itself, or multiple outbound links from one single page to another single page, are ignored. PageRank is initialized to the same value for all pages. In the original form of PageRank, the sum of PageRank over all pages was the total number of pages on the web at that time, so each page in this example would have an initial value of 1. However, later versions of PageRank, and the remainder of this section, assume a probability distribution between 0 and 1. Hence the initial value for each page is 0.25.

    The PageRank transferred from a given page to the targets of its outbound links upon the next iteration is divided equally among all outbound links.

    If the only links in the system were from pages B, C, and D to A, each link would transfer 0.25 PageRank to A upon the next iteration, for a total of 0.75.

    PR(A)= PR(B) + PR(C) + PR(D).\,
    Suppose instead that page B had a link to pages C and A, page C had a link to page A, and page D had links to all three pages. Thus, upon the first iteration, page B would transfer half of its existing value, or 0.125, to page A and the other half, or 0.125, to page C. Page C would transfer all of its existing value, 0.25, to the only page it links to, A. Since D had three outbound links, it would transfer one third of its existing value, or approximately 0.083, to A. At the completion of this iteration, page A will have a PageRank of 0.458.

    PR(A)= \frac{PR(B)}{2}+ \frac{PR(C)}{1}+ \frac{PR(D)}{3}.\,
    In other words, the PageRank conferred by an outbound link is equal to the document's own PageRank score divided by the number of outbound links L( ).

    PR(A)= \frac{PR(B)}{L(B)}+ \frac{PR(C)}{L(C)}+ \frac{PR(D)}{L(D)}. \,
    In the general case, the PageRank value for any page u can be expressed as:

    PR(u) = \sum_{v \in B_u} \frac{PR(v)}{L(v)},
    i.e. the PageRank value for a page u is dependent on the PageRank values for each page v contained in the set Bu (the set containing all pages linking to page u), divided by the number L(v) of links from page v.
  • Jim Munro: This is really, really old.

    You can tell this from this para which is no longer accurate, "The PageRank transferred from a given page to the targets of its outbound links upon the next iteration is divided equally among all outbound links".

    PageRank is moot these days. Google does not share PageRank so you have no way of validating any hypothesis. Google is still using PR internally but I would not spend a second agonising over it.

    I am not an expert but I think you would be far better served by spending your time linking out where relevant and useful and earning inbound links that you deserve. Other people might have a different opinion but I think it is a colossal waste of time.
  • Dave Elliott: I am no expert, but, Jim is right. Although i'd add that this is something you should never really have cared about. a) that is ridiculously complicated and b) it was never that simple.
    
  • Edwin Jonk: From the expert panel in this week's SEO Questions hangout on air on 00:10:00 into the YouTube video:

    If our assistance with this issue was useful to you, please consider sharing your success story so that others might benefit.
    
  • On Page Assistant: I'll answer it from an old perspective. We know that links count as votes to a particular webpage. Pagerank on the other hand is the weight previously given by Google to all those votes that are counted for a page. In a simpler term, it can be illustrated this way: One girl is searching on Google for a handsome man and because there are more handsome men that you can count, Google looks on who's voted by most magazines. One man was voted by a hundred local magazines. There's this 2nd man which has been voted by 99 local magazines and 1 international magazines and so it picks this man and placed it on page 1 position #1.

    Today this has never been much of a concern because Google stopped updating its pagerank. I even have a number of sites which have high PR but they don’t rank as much as my properly SEOed sites which have n/a as pagerank. Even before, Google is more concerned about relevance. Even if you have links from sites having PR9 but they are not relevant to your website, you are not getting much linkjuice from these sites. Today, relevance remains a factor and so we need to concentrate more on that aspect than concentrating on getting high PR links.

    

View original question in the Dumb SEO Questions community on Facebook, Tuesday, December 1, 2015).

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