Why PageRank says nothing about rankings
Sometimes you’ll get clients who say “my PageRank is x, yet I don’t get any visitors from Google”?. Understandable, I think. If you were graded 6 out of 10, by the biggest search engine out there, it’s only fair to expect some traffic, or isn’t it?
PageRank is based on the academic system of citing other people. In this system, he who is cited the most is considered the most influential. This idea was translated to the web: a link was seen as a citation, and the site with the most links, was considered the best.
This algorithm has changed over the years, in a way that is not really far away from these academic roots. In the academic world, each field of research has it’s own journals. The importance of these journals is measured using the Impact Factor, a measurement of the amount of citations of articles in that journal. Now, a citation from a journal with a high Impact Factor is more important than a citation from a journal with a low Impact Factor. Sounds a lot like how PageRank has evolved, doesn’t it?
There’s a difference though. Impact Factors and Citation Indexes are only used in the academic world to compare people and journals within a certain field. If you look at the journals with the highest impact factors, you will see that these are almost all health related, because this is the largest portion of the research industry. Someone might think the American Sociological Review is an unimportant journal, since it’s Impact Factor is way lower than that of “less important” medical journals. It is however, the most important journal for people studying sociology.
What does this teach us? PageRank is useless without context. You can use PageRank to compare yourself to other sites in your branch, and it’ll have some more meaning, but even that won’t guarantee you any results.
As it works now (for all we know), you get a higher PageRank as well if you get links from high PageRank sites that aren’t related to your business. It’s like getting quoted in a high rank medicine journal with your history research: nice, but it won’t get any of your colleagues, your intended audience, to read your research. Next to that, it doesn’t say anything about the quality of your research. We can’t expect an editor at a medicine journal to correctly assess the value of history research, can we?
Google looks at links like these the same way: the only way to get higher up in the rankings for your branch, is to get peers to link to you. Links from sites that match yours on topic, that’s what you need to rank higher on your subject of choice.
Summing up, this means that the only thing PageRank measures is the amount of your incoming links, and it says nothing, really nothing, about your rankings, or search engine traffic.