tedster - 7:19 am on Apr 23, 2010 (gmt 0)
I'm not just sharing a belief here. I've been doing SEO as my entire career from before Google was invented. Then I followed the development of PageRank and the rest of Google's algorithm very closely as it evolved.
Many people have had a tough time understanding PageRank from the beginning of Google. That's because PageRank is an iterated function, and the math around that can be a bit unfamiliar. But I don't want to see anyone get even more confused.
Here's why you see only a little change in PageRank even from a lot of links.
PageRank on the toolbar is approximately a logarithmic scale. That means going from a PR-2 to a PR-3 takes EXPONENTIALLY more links than going from PR-1 to PR-2 did. Then going from a 3 to a 4 takes an even bigger jump, again exponentially.
Since all we ever see is a change in steps of 1 PR unit, that means we can get a LOT of links and still see only a small change in PageRank -- or even no change at all.
In addition, PageRank is only exported to the toolbar about four times a year. That means we can't even see the effects of our backlink growth on PageRank as it happens.