37 PR10 Pages Drop to PR9's
When there is a toolbar PR update lots of things change. The Search Engine forums discuss these changes and post their findings and theories and the SEO community lookings over all the changes and theorize why the different things have happened.
I keep a list of all the PR 10 Pages (<!-- m --><a class="postlink" href="http://www.seocompany.ca/pagerank/pr-10-pages.php">http://www.seocompany.ca/pagerank/pr-10-pages.php</a><!-- m -->) and Page Rank 10 Sites (<!-- m --><a class="postlink" href="http://www.seocompany.ca/pagerank/page-rank-10-sites.php">http://www.seocompany.ca/pagerank/page- ... -sites.php</a><!-- m -->) on the internet. This Oct 6th PR update saw 37 out of 152 PR10 pages drop to PR9's. This post takes a look at one of the theories why this has happened.
The following are the PR10s that moved to PR9s for each company. Adobe 4/51 pages, Apple 7/27 pages, Google 7/35 pages, MicroSoft 5/6 pages, w3.org 2/4 and nsf.org 1/2 pages. Beside these pages there were 11/28 sites that had their only PR10 page drop to a PR9.
One theory why this has happened is that real PageRank has a maximum value of the number of pages in Google's index. As the index gets bigger the real PageRank number increases.
Markus Sobek in his article A Survey of Google抯 PageRank (<!-- m --><a class="postlink" href="http://www.miswebdesign.com/resources/articles/pagerank-3.html">http://www.miswebdesign.com/resources/a ... ank-3.html</a><!-- m -->) theorizes that the real PageRank has a maximum value of dN+(1-d) where N is the total number of web pages in the index (d is usually set to 0.85), and that a real PageRank is scaled to be displayed on the Google toolbar. It is generally accepted that this scalation is logarithmically.
The main reason it is assumed that the toolbar scale is logarithmic is as you go up the scale it takes many more links to get a PR3 then it takes to get a PR4 or PR5. Also the small number of pages that reach PR10 shows this also..
When the real PageRank numbers increase, the range of each of the toolbar scale units moves up. When this happens the lower range of real PageRank in each toolbar unit (except the toolbar PR1 as it covers the very bottom of the real PageRank numbers) is then covered by the toolbar PR value below. Some hold that this is why 37 PR10's slipped to PR9's in this toolbar update. (The below graphic is not to scale but gives you a visual of the theory of what has happened.)
<!-- m --><a class="postlink" href="http://www.seocompany.ca/images/new-old-scale.gif">http://www.seocompany.ca/images/new-old-scale.gif</a><!-- m -->
Research is still being done to find all the new PR10 pages and new sites that have picked up PR10 pages. I will be doing a post my findings some time next week
When there is a toolbar PR update lots of things change. The Search Engine forums discuss these changes and post their findings and theories and the SEO community lookings over all the changes and theorize why the different things have happened.
I keep a list of all the PR 10 Pages (<!-- m --><a class="postlink" href="http://www.seocompany.ca/pagerank/pr-10-pages.php">http://www.seocompany.ca/pagerank/pr-10-pages.php</a><!-- m -->) and Page Rank 10 Sites (<!-- m --><a class="postlink" href="http://www.seocompany.ca/pagerank/page-rank-10-sites.php">http://www.seocompany.ca/pagerank/page- ... -sites.php</a><!-- m -->) on the internet. This Oct 6th PR update saw 37 out of 152 PR10 pages drop to PR9's. This post takes a look at one of the theories why this has happened.
The following are the PR10s that moved to PR9s for each company. Adobe 4/51 pages, Apple 7/27 pages, Google 7/35 pages, MicroSoft 5/6 pages, w3.org 2/4 and nsf.org 1/2 pages. Beside these pages there were 11/28 sites that had their only PR10 page drop to a PR9.
One theory why this has happened is that real PageRank has a maximum value of the number of pages in Google's index. As the index gets bigger the real PageRank number increases.
Markus Sobek in his article A Survey of Google抯 PageRank (<!-- m --><a class="postlink" href="http://www.miswebdesign.com/resources/articles/pagerank-3.html">http://www.miswebdesign.com/resources/a ... ank-3.html</a><!-- m -->) theorizes that the real PageRank has a maximum value of dN+(1-d) where N is the total number of web pages in the index (d is usually set to 0.85), and that a real PageRank is scaled to be displayed on the Google toolbar. It is generally accepted that this scalation is logarithmically.
The main reason it is assumed that the toolbar scale is logarithmic is as you go up the scale it takes many more links to get a PR3 then it takes to get a PR4 or PR5. Also the small number of pages that reach PR10 shows this also..
When the real PageRank numbers increase, the range of each of the toolbar scale units moves up. When this happens the lower range of real PageRank in each toolbar unit (except the toolbar PR1 as it covers the very bottom of the real PageRank numbers) is then covered by the toolbar PR value below. Some hold that this is why 37 PR10's slipped to PR9's in this toolbar update. (The below graphic is not to scale but gives you a visual of the theory of what has happened.)
<!-- m --><a class="postlink" href="http://www.seocompany.ca/images/new-old-scale.gif">http://www.seocompany.ca/images/new-old-scale.gif</a><!-- m -->
Research is still being done to find all the new PR10 pages and new sites that have picked up PR10 pages. I will be doing a post my findings some time next week