If you have been reading SEO blogs for any length of time, you have probably read about PageRank at some point. While I personally feel there is often too much focus on PageRank, particularly when link building, there are some core concepts you should be aware of. At the very least you should understand how PageRank works and what it means for your own SEO work.
What is PageRank?
Contrary to popular belief, the name actually comes from the inventor Larry Page (co-founder of Google with Sergey Brin) and not the "rank of a page." If you fancy some in-depth reading, take a look at the original PageRank paper that Page wrote while still at Stanford University in 1999.
Here is an abstract from Wikipedia:
PageRank is a link analysis algorithm, named after Larry Page and used by the Google Internet search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of ‘measuring’ its relative importance within the set.
PageRank is measured on a scale of 0-10, with 10 being the highest. It is a reflection of the number and quality of the links pointing at a particular webpage. In general, the more links and the higher the quality of those links, the higher the PageRank will be.
At one time, we could get an idea of what the PageRank of a particular page was by using a tool that accessed the Google Toolbar which contained a PageRank score. This was officially retired in 2016 but hadn’t been updated for years prior to this. This didn’t mean, by any means, that PageRank itself was retired or that Google were no longer using it internally as a way to measure the quality and volume of links to a page.
The real PageRank is fluid and constantly changes, whereas Google Toolbar PageRank was updated every few months, if that. Real PageRank is also not measured in nicely rounded numbers, and in fact is a very long decimal between 0 and 1 which allows for calculations and comparisons across the billions of pages that Google crawls.
For this reason, you can't use PageRank as a metric for your SEO campaign - we simply can’t measure it. If you come across anyone trying to use it as a way to measure links, run away.
Some background - Bringing order to the web: PageRank
People often wonder what it was that made Google so successful and what has led it to dominate search in recent years. We talked about this briefly in the last chapter, but let’s go into a little more detail.
There are many factors that have led to Google’s success as a company and the crazy profits they generate, but in terms of pure organic search, links played a pivotal role in making their results better than any other search engine on the web. Even now, with over 84% of their revenue coming from Google Ads, it was and remains to be, the quality of their organic results which drew people toward them over other search engines.
Many search engines at the time were fully aware of how links may help give a better, more relevant set of search results. But it was Larry Page of Google who made the breakthrough that would eventually lead to search results that were far more relevant and useful to users than had ever been seen before.
Links between webpages reminded Page of citations on university papers. Scientists who published papers would cite other papers they had referred to or used in their research. These citations gave credit to the right people and meant that some scientists (and their work) became well known and influential. Page said:
It turns out, people who win the Nobel Prize have citations from 10,000 different papers. A large number of citations in scientific literature, he said, means your work was important, because other people thought it was worth mentioning.
Source: The Google Story by David Vise
Page realized that the same principle could be applied to the web to find the best and most influential content. He then realized that, like citations, some links would matter more than others, and they were not all equal. To measure how much a particular link mattered, you could look at the number of other links pointing at the page it was on.
The Google search engine has two important features that help it produce high precision results. First, it makes use of the link structure of the Web to calculate a quality ranking for each web page. This ranking is called PageRank and is described in detail in [Page 98]. Second, Google utilizes link to improve search results.
Earlier, we talked about how it was quite hard to determine the quality of a piece of content because it is a subjective decision. PageRank aims to overcome this by looking at the pages on the web and orders them by the count and quality of links pointing at them.
These maps allow rapid calculation of a web page's "PageRank", an objective measure of its citation importance that corresponds well with people's subjective idea of importance. Because of this correspondence, PageRank is an excellent way to prioritize the results of web keyword searches.
Essentially, PageRank uses the democratic nature of the web, and the opinions of webmasters, to determine the relative importance of a given page. The beauty of this system is that it scales amazingly well and allows for pages (and therefore content) to be objectively compared and ranked with a high level of confidence.
This was the breakthrough that allowed Google to push ahead and give their users more useful search results. This breakthrough was based on links, pure and simple. While other search engines were relying on keyword relevance to a page to rank search results and generally not going a great job, Google was taking all of these existing factors and factoring in their PageRank algorithm to deliver a highly relevant set of search results.
However, it wasn’t PageRank alone that helped Google deliver more relevant search results – Google also used anchor text to help determine the context of the page that was being linked to. I should also mention that as Google gained traction, it was able to leverage user data a lot more and introduce elements of machine learning into their algorithms.
How much should I care about PageRank?
As a concept, you should be aware of PageRank because it plays an important role in ranking and is likely to for a long time to come. If you’re going to build links, you should at least familiarise yourself with how PageRank works. It is also an important concept when it comes to internal links i.e. your website architecture. PageRank flows between your own pages as well as from external links. This means that you want to ensure that your key pages are well linked to, giving them as much PageRank as possible and therefore, the best chance of ranking well. If you want to read more about this, I'd highly recommend this guide from BuiltVisible on internal linking and website architecture.
At the same time, it’s something that we can no longer measure at all, so it’s not something that you should worry about much day-to-day. Given that we can no longer even get an idea of PageRank score for a page, it’s worth steering clear of anyone who still uses it as a real metric.
A quick word on PageRank sculpting
The theory behind PageRank sculpting is that you can use various methods to control the flow of PageRank between pages on your website. Therefore, you can flow PageRank to pages, such as your category and product pages that you want to rank well in search results. In theory, you could also preserve the PageRank of a certain page by restricting the flow of PageRank from that page, too. However, Google has publicly said that it actually prevented this method of PageRank sculpting from working, which drove hot debates among respected SEOs, who had been preaching this method for quite some time.
This is a pretty old tactic now, having first been talked about publicly around 2007. Generally, it’s not something to worry about or obsess over too much because, as mentioned above, you can’t measure PageRank anyway.
My own opinion is that you should care about your pages getting enough PageRank to rank well in search results. Rather than worrying about keeping PageRank on certain pages by not linking out, you should focus on enabling the flow of PageRank to key pages. This manifests itself by having good website structure, both for users and search engines, and having key pages as close to the homepage of your website as possible. PageRank alone shouldn’t be a reason for this. After all, you want real users to find your key pages, so you should make sure they can find them easily!
The role of anchor text
PageRank allowed Google to determine the quality of links using a consistent, scalable metric. However, Google wanted more signals to help give users the best search results and realized it could extract a signal of relevance from the links it was already recording. Anchor text as a ranking signal was born.
Larry Page and Sergey Brin realized that the keywords used as the anchor text of a link could be used to determine relevancy of the page being linked to. They explained this in the following way:
The text of links is treated in a special way in our search engine. Most search engines associate the text of a link with the page that the link is on. In addition, we associate it with the page the link points to.
As an example, if Google found that a particular page had links pointing to it with the anchor text “wooden toys,” it may be more likely to show that page to users who searched for “wooden toys.” The implication is that the anchor text is a good way to figure out the topic of a page that is being linked to, without actually visiting the page. It worked remarkably well as a ranking signal and again, helped Google produce better quality results than their competitors.
However, it soon became apparent that anchor text was a very strong ranking signal for Google. SEOs of the time capitalized on this by building lots of links using the keyword they wanted to rank for as the exact anchor text. At the time, because Google was relatively new and there weren’t that many other signals, this was usually enough to get a number one position in Google.
Even today, anchor text is still a strong signal and is referenced in the Google starter guide to SEO, although 2012 saw the Penguin update which sought to penalize for over-optimization of various signals. One of the signals believed to be affected was anchor text, and many SEOs reported seeing penalties on websites that had a high percentage of commercial anchor text in their link profile.
Therefore, it’s not something that should be focused on or pursued. The focus should be on the quality and relevance of a link instead of the anchor text that is being used. Also, it isn’t exactly natural to have lots of links with the exact same anchor text (which also happens to be a target keyword) in your link profile.