Jul 242007

Scaling The Google PageRank Mountain

Humans are linear thinkers. We have trouble grasping exponential growth, as Ray Kurzweil eloquently points out.

Google PageRank is such an exponential function. It is log-transformed to make the numbers small and friendly, just like the Richter scale. In both PageRank and earthquakes, a 7 is much larger than a 6. An 8 is much much larger than a 7. And a 9... well, you get the idea. Because PR scores are log scaled, because they're small and easily grasped, because they fit on the fingers on two hands, it is too easy to lose the sense of their exponentiality.

Search Engine Land started a new column in May called Search Illustrated, which presents concepts in search marketing graphically. The May 8th post, Search Illustrated: Google PageRank Explained, offers this cool representation of PageRank as a mighty mountain.

Google PageRank, graphic reproduced from Search Engine Land

Note the big red blowup section. On the full mountain, this red zone occupies just the smallest bottom smidge on the bottom left of the full mountain.

PR 0 through 7, represented in the blowup section, only takes you up to tree line. 8 is just above treeline. 9 is alpine, but still far below the snow line. And the elusive 10 is the summit -- supplemental oxygen clearly needed.

While the mountain is an inexact visual metaphor, it does give a strong sense of the non-linear nature of PageRank.

Cool graph, SEL!


9 Responses to "Scaling The Google PageRank Mountain"
Shortshire says:
That is a pretty sweet picture. I always thought page rank was exponential but I didn't think there was that much difference. Thanks for pointing that out to me.
Johann says:
What should be noted is that the amount of low-PR pages is probably a lot larger than this image would suggest.
Excellent point, Johann. It is so hard to display exponential trends in a comprehensible way. If the mountain was really to scale, it would be so wide at the base it would look like a huge flat pancake with a really thin tall sharp needle coming up from the middle, or something like that. And if you take logs, the data fit nicely, but our brains are inherently linear in their perspective, and most people can't get a true sense of scale after data have been logged. Elliance's graph is more a metaphor than an accurate presentation, but even as metaphor, I think the image is quite cool and a good teaching tool. Thanks for the comment!
I love that image. Shows you pretty much how much work you have to do to "scale the mountain"
I agree with Alan, it should look more like those exponential curves we all plotted in school, but the mountain does brilliantly demonstrate the great difficulty in moving up just one step in rank, not to talk of 2-3 steps. Apparently ther are fewer than 200 PR10 pages and Adobe lead with over 40 of the top pages - probably due to the ubiquity of flash, pdf or other multimedia files and programs.
I wish I could see the actual figures of how many sites have each page ranking - that would be fascinating. Like the illustration above, but to scale. I'm reading a lot about Page Rank at the moment, because I thought it was this illusive beast, but then yesterday the blog at our .com startup suddenly had a PR of 3. Not very big, but we only have 8 incoming links, and we haven't even launched the site to the public yet (only 3 or 4 of our pages are indexed and we will be launching around 1000 pages at the end of the month). I don't get it, why did Google suddenly decide that we're worth something? Not that I'm complaining...
Good question! One reason we never got into SEO services is: we don't think anyone knows the answer to this kind of question, Google included.
Alan, Thanks for the visual. I'm just trying to move my SEO knowledge from passable to mastery and this page really helps depict the huge amount of difference there is between pr2 and pr 4. Thanks! Joseph


Check out what others are saying...
[...] I have never heard anyone explain PR in the way that it is visualized in this graphic: http://www.rimmkaufman.com/rkgblog/2...rank-mountain/ Yes...rather eye-opening isnt it? Observe how the large blow-up of PR1-7 scale is really just a [...]

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