Google's PageRank metric has become rather controversial. Some SEOs will argue that PageRank is now entirely meaningless. Are they right?
No. The application of PageRank has changed but PageRank still counts.
In the old days of SEO (a few years ago) a high PageRank would almost always equate to a high rank in Google. PageRank was so influential that people paid serious money to take control of domain names that had an enviably high PageRank.
PageRank is determined by links.
The original Google paper (Larry and Sergey's academic offering) presented a PageRank that was compiled through the equation:
PR(A) = (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(Tn)).
There are three key points to notice in that original equation.
1. (1-d) + d is a damping factor. From day zero Google could turn the dial to make a high (absolute) PageRank harder or easier to get.
2. PR(T1) (up to Tn) represents the PageRank value of the pages which link to the target page.
3. C(T1) (up to Tn) represents the number of outbound links on the pages which link the to target page.
PageRank is often summarised as "the worth of pages pointing to your page".
Another way to think of PageRank is as a probability measurement. The original PageRank was designed to represent the chances of someone discovering your web page if they randomly clicked on links in the internet. At this point it's worth noting that Google has far better ways of determining how likely people are to visit your web page today.
So, what about the PageRank of today?
It's safe to conclude that the PageRank formula has evolved but that it is still concentrated around links. When Google announced its crackdown on websites and search agencies that were buying links in order to boost their search position - Google said that companies could advertise in text if they so wished and that Google was only acting against links which were bought to effect PageRank.
Google keeps its PageRank tallies up to date, however the PageRank which we can see is kept "out of date" by several months.
The most common way to view a web page's PageRank is to download the Google Toolbar and configure the advanced options. It is also possible to view PageRank at Google's Directory. Note that the toolbar PageRank is a value measured from 0 to 10 and the directory is measured from 0 to 8.
It is best to think of PageRank as one of hundreds of Quality Signals that Google uses to evaluate where web pages (pages, not sites) should be ranked today.
Google also uses PageRank in two key areas:
1. Determining how often to re-visit and re-crawl the site. A site like the FT has a high PageRank and Google keeps close tabs on the homepage and quickly looks at new web pages which are linked to from it.
2. Determining how deep to crawl from a page. For example, bigmouthmedia has lots of content pages, news stories and archives which date back years and this is rare for a digital marketing agency. However, the homepage has a high PageRank and so Google is happy to explore down to the archives. A site with a lower PageRank may find that its archives are ignored.
Is it worth fussing about PageRank?
It is certainly worth being aware of PageRank but it is not worth obsessing about it. A site can enjoy a successful search marketing campaign and high positions without having a high PageRank.
A high PageRank is reassuring and does show that Google seems to be looking at the site in a positive light. However, I would rather double my traffic than my PageRank.
Some people buy links based on PageRank. A link from a high PageRank site costs more than a link from a low PageRank site. This harks back to the original PageRank formula where the inbound link from the high PageRank site would be worth more. That may still be true today but these days Google also considers this.
One of Google's first reactions when it suspects sites of link selling and link buying is to disable the suspected link seller's ability to "pass PageRank". This means that the link seller does not lose any of its own rankings and the suspected link buyer is neither penalised nor awarded for the bought link.
At this stage in Google's reaction, all the high PageRank link has done is cost the SEO agency or their client money - for nothing in return.
PageRank has evolved over time and its direct influence on search positions has changed. The metric is worth being aware of but not worth sweating over.
Andrew Girdwood is head of search at bigmouthmedia.