rekitty - 8:20 pm on Apr 7, 2007 (gmt 0)

Great thread. Yes I believe there has been a fundamental change in Google. Tedster, I believe your re-ranking is a major change, but not the fundamental change.

The fundamental change I see is Google has significantly altered the calculation of link popularity by relegating a large percentage of pages to the supplemental index where their links don't count.

Previously every page on the web had a vote as long as that page was found by googlebot. If a page was not found for a couple months or if it had duplicate content it was put in the supplemental index. Supplemental pages didn't get votes because they could not be trusted. Not a big deal because only a small percentage of the web was supplemental. The supplemental index was primarily the garbage collector where pages went to wither.

Today is very different. The supplemental index plays a key role in Google's new architecture and a huge percentage of pages are sent to the supplemental index for many different reasons. These pages no longer rank well, making some noticeable changes in the serps. The huge effect, though, is all these supplemental pages no longer pass link popularity from what I can see.

I think of it as an election where half the voter registration cards have been torn up. The election results will be very different. Did only folks over 40 get to vote? Or was it a particular income level or religion that voted? Who you let vote will result in very different politicians being elected.

Google was sneaky. They didn't tear up all the voter registration cards at once. Rather each day for the last year Google went door to door and tore up a few voter registration cards. In the constantly running election of Google serps nobody noticed the small changes as they happened each day.

We've been in the middle of a slow boil update. Nobody jumped out of the water or even noticed the fundamental change because it happened slowly over months. Just one observer's opinion.