Understanding Page Rank (PR), Link Juice and Link Distribution The Easy Way

 

While the exact nature of how Google and other search engine do their ranking for each web page on the internet is still unknown, the concept of back link, link juice and link love has been so far quite easy to model the search engine ranking. If you still have a little bit vague understanding about it, be sure to read this article to strengthen your understanding of one of the most important SEO aspect: link popularity.

Each web page got a beaker glass….

Imagine, each web page has a beaker glass (as pictured on the right). Each web page, not website. So a website with 8 different pages have 8 of this imaginary beaker glass on our SEO lab.

Now also imagine, at the beginning of the www universe, the google spiders a.k.a google-bots (and other spider)  are deployed. Each time they finish reading 1 page, they will give 1 drop of “link juice” (just imaginary liquid for this analogy). Hence, if a web page is very popular, the bot will pass the page over and over again - each time giving the page 1 drop of link-juice.

The result is some website have more juice than the other. Then according to its amount on the scale, the rank is given.

How the spider jumping around from page to page

Now, how the spider or the bots go from one web page to another? The starting point of course if up to the owner of the spider, but the continuation will be up to the content of that page. For example: a bot is deployed on www.cnn.com/index.htm. The bot then do its thing (read the page, indexing, grab the content, etc) and list all the web link (anything pointed with <a href=”"> tag). Then it will go to each one of the link on the list. Remember, each time, giving a drop of link juice after the page is read.

This is where all the fuss about “nofollow” command/attribute. Some link has “nofollow” attribute. When a bot see the attribute, it will remove the link from its “go to” list, hence that link will not be visited nor get any link juice. But not all bot obey thid command/attribute.

Therefore, if you have 1000 web page linking to your web page, then your web page will potentially get that 1000 drop of link juice.. and more….

Additional Juice from every web page….

All expert in SEO world would agree, 10 back links from  web pages with PR5 will be much more valuable than 10 links even 20 links from web pages with PR1. How this can be accomodated in out model above.

Remember the bot will give a drop of juice every time it has read a page? Now imagine, every time the bot will go to each of the link on your page, it will also carry additional juice from your page away. To make it easy, imagine for each a PR1 page the link will give additional 1 drop, PR2 additional 2 drops and so on.

For example: your homepage has PR5 and there are 20 link on your page. So, for each of that 20 pages, rather than getting only 1 drop of juice, they will get 6 drop of link juice (1 from the bot, 5 from the home pages).

So, this will explain that a backlink from a higher PR page will be more valuable than the one without PR because they carry more link juice. But it doesn’t mean that the link from PR zero is worthless, no… because you will still get a drop from the bots.

Residual juice…

To make it more complicated, the bots also can do residual carry of the juice. Meaning the link juice from a high PR page can be passed on further down the line but in decresing amount.

For example , let’s go back to your homepage that has PR5 above. It has 20 link, right? One of the 20 is “about us” page. The “about us” page got further 5 links. Say this “about us” page doesn’t have any PR. Then the further 5 links will have 1 drop from the bots, zero from “about us” page plus some residual from homepage, say 4 drops – totaling 5 drops.

Therefore, this will explain why web page that indirectly link from high PR website also get advantage of its valuable link juice (thinking about Paul’s or Angela’s back link strategy)

Seamlessly in secret.

Of course , in reality, there are some further altering  of parameters and adjustments. No one really know exactly. But the model above will help you understand pretty much the gist of the link building and link popularity understanding.

Hope this helps….

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