The PageRank method is one that determines the importance and relevance of Web pages when a specific query is issued in a search engine. This method is responsible for the great success that Google has run into in the past few years. In Networks, Crowds, and Markets, our class textbook written by David Easley and Jon Kleinberg, Chapter 14 is dedicated to exploring this topic. In the text, there is a clear definition that captures how this method works. First, in a network with n nodes, we assign each node an initial PageRank value of 1/n. Next, we choose a number of steps, k, which represents how many rounds we will be performing on the network. Then, we perform a sequence of k updates to the PageRank values, using the Basic PageRank Update Rule. This rule states that each page divides its current PageRank value equally across its outgoing links, and passes equal shares to the pages it points to. If a page does not have any outgoing links, it passes its current PageRank value to itself. Finally, each page updates its new PageRank score to be the sum of the shares it receives.
This is the basic idea behind this mechanism. Google uses a slightly altered version of this method, but they both accomplish the same goal in the end. In 2000, Google released its first toolbar for Internet Explorer. Essentially, this toolbar was supposed to make searching easier than ever before. It also had a feature that, when enabled, a PageRank meter would be displayed and the public would know how important and relevant the page that they were viewing was. This was especially useful for search engine optimizers.
However, SEOs got caught up in a frenzy about these PageRank values. Everybody wanted a higher one and the demand for them was astronomical. As a result, a market emerged to accommodate their growing need for a high PageRank. Link-selling became one of the best ways to make a profit from the SEOs who were doing anything to make their PageRank value increase. People would buy these links and in turn, their PageRank would go up, and then Google would rank their pages higher for different terms.
Google was not happy with the manipulation of its top strategy. Google began to penalize the markets that allowed the selling of links to improve PageRank scores by reducing their PageRank scores or by removing them from Google’s services altogether. This was not the end to link selling, though. The demand for a higher PageRank value was still as high as ever and the networks that sold the links went underground. When one was closed, another would open, and this cycle was not going to end soon. Link spam started to occur and people were putting links into as many pages as possible just to get the boost in their PageRank score. In 2005, Google was urged to do something to stop the link spam from occurring. They tried to fight against it but their tactic did not work.
Google has obviously changed its services since 2000, creating its own browser that allows searches to be made in the HTML bar. Most of Google users made the switch from Internet Explorer to Google Chrome. Chrome does not offer such a toolbar to be installed, so people could not use this as a way to check the PageRank scores of all Web pages. Instead, the scores were reported through Google Search Console. This was abandoned in 2010. Now, the only people who are able to view the PageRank scores are the ones still using a version of Internet Explorer that allows for the toolbar to be installed and used actively. The number of people using Explorer has dropped incredibly recently. Google has recognized this and will soon make the toolbar inaccessible to everybody. No one will be able to know a page’s PageRank score publically. Google will become the only entity that has access to these scores.