Pagerank is one of the tools Google uses to determine the quality and importance of a page relative to a specific search query.
Pagerank
Google developed Pagerank in the late 1990s as part of its toolset to determine which pages will show up for a given search, and in what order. It is important to note that PR is only one of the tools they use, and its weight in the ranking process is a part of the Google ‘blackbox’.
At its most simplistic, Pagerank is a popularity ranking used to determine the likelihood that a person will wind up on a particular page if they randomly clicked on links throughout the internet. As you can imagine, given the number of pages, this will render a rather low likelihood for most pages.
Augmenting this ‘randomness’ is a lot of mitigating inputs. Quality of pages plays linking, ‘normalcy’ of the linking profile (the mix of all pages linking to a page), and according to Google, the quality of the linking pages as well as other factors that are not made public.
Link Spamming
As one can imagine, in the early days of SEO work, there was a lot of blackhat SEO going on, trying to game the Pagerank Algorithm. One of the techniques was to create as many links to a website as possible. One tool among many was link farms; a series of loosely (or even closely) connected sites that did nothing other than sell links to other sites.
It didn’t take Google long to identify these techniques and warn site owners away from them. Unfortunately, many dismissed Google’s warning.
Google Penalty
From a technical perspective, identifying a site that is trying to game the system was not hard for Google. At first, Google tried to ‘play nice’ and tell people they shouldn’t do this. Then, they took the gloves off and penalized pages and perhaps evens sites, the engaged in this activity. The penalty box pulls the money pages of a site from the SERPS, required extensive mitigation activities, and was usually difficult to overcome.
It didn’t take long for competitors to take advantage of this. Before long, webmasters were spamming each other’s sites. Through no fault of their own, owners found their sites suddenly delisted in the SERPs.
Google steps back on the spam penalty
Google changed tactics. Rather than delist a site for a spammy profile, it began dismissing the suspicious links. So, while you won’t be penalized for overly aggressive link building, you won’t get credit either. Spamming becomes a waste of resources.
Link Building
Is link building worth the effort (and money)? In short, yes. Without links to your site, Google will not put it in the SERPs. But, you need to balance the link-building efforts and your content development and technical efforts. A bunch of links to bad content, or content that can’t be properly indexed, will not get you in the SERPs.
Link-building programs are beyond the scope of this article. If you are not familiar with link building, check out a couple of articles to give you a basic understanding.
Link Building, what is it. and What are 2nd and 3rd Tier Links?
Passing Pagerank
While we don’t know the Pagerank algorithm, there is a simple way to think of it. Each page is assigned a Pagerank number (between 1 and 100). Part of the Pagerank is passed through to each of the links from that page to the pages it is linking to. There are some companies, like MOZ’s Domain Authority and Page Authority, that created a proxy for PR, and have been able to model PR very closely… at least until Google stopped publishing Pagerank.
Pagerank no longer visible
Google stopped publishing Pagerank a number of years ago. Before they stopped publishing completely, they scaled back the frequency. So, today, you don’t actually know your Pagerank. But, as mentioned above, there are companies that developed proxies for PR and were able to track to it very closely while it was being published.