Measuring Link Value in SEO - Link Authority Unit Defined

 (Published Article EzineArticles.com)

It is a scientific principal that everything that can be measured should have units of measurement. This is true whether we consider distance, volume, weight, currency, temperature or anything else that lends itself to measurement. In relation to links on the internet, also called backlinks, it has become fashionable to use the term 'link juice.' Link juice, however, is still a concept and not a measurement. Nobody would suggest that the total value of incoming links to a web page is 1.7 ml.

Google changed the face of SEO (search engine optimization) in 1998. Until then, search engines looked at on-page factors only to determine positioning on search engine results pages. Larry Page and Sergei Brin, the co-founders of Google, realised that the best web pages on a subject would have most high quality links. Surprisingly, there is no measurement applicable to link value. A unit of measurement is clearly required for link value.

Central to the Google algorithm, which determines position of web pages on Google's results pages, is 'PageRank'. This term is in itself misleading. It is comprised of two words - page and rank. PageRank does not refer to either a web page or its ranking (or positioning) on Google's results pages. 'Page' is derived from the name Larry Page and 'rank' is the relative authority or popularity of the page. If only the two brilliant mathematicians had called it LarryAuthority or SergeiPopularityScore or something to that effect.

PageRank, regardless of nomenclature, is the most important factor in the Google Algorithm (EzineAriticles, Viniker, D.A. May 2010). If you are not familiar with PageRank, you will need to have the Google toolbar installed and it is available on the Internet Explorer and Firefox web browsers. The PageRank indicator is a horizontal bar. The most authoritative web pages (e.g. Google.com) have a PageRank 10 and the PageRank indicator is completely green whereas a new web page will have a PageRank 0 and the indicator is completely white.

Hovering the cursor over the bar reveals "PageRank is Google's view of the importance of this page" followed by the score e.g. 10/10 for Google.com. I would emphasise that this is again misleading. It is the PageRank of the home page of the website that is Google's view of the importance of this page! (EzineAriticles, Viniker, D.A. May 2010). The total link value required for each step in PageRank is on a logarithmic scale (EzineAriticles, Viniker, D.A. June 2010).

Four of the top five factors in the Google algorithm relate to backlinks - incoming links from other web pages according to the top 72 international SEO experts, (SEOMoz). The total value of the incoming links to a web page provides that page with its "authority". The value of each link depends on the authority of the linking page (PageRank) and the number of outgoing links on that page.

PageRank is calculated by adding up the value of each incoming link. The value of the link depends on the PageRank of the linking page and the number of outgoing links on the page. Link value = PR / x where PR is the PageRank of the linking page and X is the number of outgoing links on that page.  

The full value of a link does not reach the receiving page. According to Matt Cutts, the well-recognised Google spokesman, if this were to occur, the system would implode. And so Google removes a % of the link value which is about 15% - a sort of Google tax.

Incoming links benefit a web page in at least two independent ways. Firstly, they give authority to the page and the website. Secondly, the anchor text (link text) informs the search engines what others consider the web page is all about.

It is proposed that we use "link authority unit" for the value of links. One link authority unit is defined as the value of a link from a web page of PageRank 1 with one outbound link. Thus the value of a link from a page of PageRank 5 and with 10 outbound links would be 0.5 l.a.u. 

Original Publication - http://ezinearticles.com/?Measuring-Link-Value-in-SEO---Link-Authority-Unit-Defined&id=5476460