Google PageRank is perhaps one of the most widely discussed phrases on the Internet. It’s a complex concept and if you would like to understand it in more technical detail one of the references at the end of this post can help you. Here we will discuss some of the broader issues involved in thinking about Google PageRank.
Google PageRank is a mathematical value that Google calculates for the web pages indexed in its databases. Users of the Google Toolbar can also see a graphical representation of the PageRank. This looks somewhat like a thermometer and displays a value from zero to 10. It is this latter Toolbar PageRank that people often refer to when talking about PageRank. This simplified representation is only updated from time to time, whereas the underlying PageRank value is presumably updated more frequently. The PageRank is an indication of how important a page may be. It is determined by the number of links from other web pages that a given web page has
The Toolbar PageRank for the web pages in their website is often a source of pleasure to some webmasters and a source of pain to others. A PageRank value of 5 or more indicates a webpage that has some degree of importance or authority. A PageRank value of 0 indicates that Google attaches little importance to this particular webpage. Indeed many web pages end up in the Google Supplemental Index and have a PageRank of 0. As a side note on this, the PageRank will also determine the frequency with which the search engine spiders or robots recheck the content of web pages. This is why it is so difficult when web pages fall in to the Supplemental Index since they will then be re-examined only very infrequently.
Recently selling links from web pages has been seriously questioned but nevertheless a high-ranking web page can represent significant revenues if its owner chooses to sell links from it. Since the Toolbar PageRank scale is exponential, like those used to rate earthquakes, a PageRank of 7 or 8 has much more power than one of 3 or 4. Links from such high-ranking pages command correspondingly higher fees. Such links pass a greater degree of importance to the target web pages.
Although PageRank is said to be one of the more than 100 factors that are involved in Google’s algorithm for determining key word relevance, it seems to have a very powerful influence. If keyword search results for Google and for Yahoo! are compared, it will be found that content of a webpage often is much more influential with Yahoo! In a sense Google seems to be more impressed by the authority of a page than by its content.
You can get a sense of this if you compare the same keyword search in Yahoo! and Google. Yahoo! will give you what you asked for. That is a list of possible web pages that may be relevant to your keyword query. Google on the other hand shows you what may be described as a work in progress. A given relevant web page may be followed by an indented other web page on the same website and a link to other web pages on the same site. You asked for a list of web pages. Google comes back now with a whole website that may be of interest. This is presumably because Google feels the ‘reputation‘ of that website is high and any other web pages may be of interest even if not so ‘relevant’. I believe Google may be testing more Yahoo-like search engine result pages (SERPs) recently and it will be interesting to see how this evolves. All the search engines are constantly improving their algorithms so any such statement can only represent a current view.
This week, William Slawski discussed a New PageRank Patent from Stanford. Some of his comments provide a useful caution in thinking how PageRank may evolve.
Perhaps the biggest takeaway from the issuance of this patent is that the original PageRank, described in the late 1990s in The Anatomy of a Large-Scale Hypertextual Web Search Engine and The PageRank Citation Ranking: Bringing Order to the Web, has changed and evolved over time. The processes that the major search engines follow to calculate a query independent score for pages (an indication of how important a page may be rather than how relevant it may be for a specific query) may not have followed along the same path as the academic research on the subject.
Although some might prefer that all discussion of the Google PageRank be avoided, for Google it has been a marketing coup. It is now an important part of their brand equity. Even if their search algorithms were to place less emphasis on it, it is most unlikely that PageRank will disappear any time soon from the Google Toolbar.