dickbaker - 6:07 pm on Feb 28, 2011 (gmt 0)
It looks to me like something was added to the algo that devalued sites rather than a changed the ranking order. None of the SERPs I look at changed with sites moving up and down and all around. Sites got devalued. Other sites moved up as a result of them moving down. Does anyone else have this view?
No, I think it's a combination of devaluing sites to some extent, and then devaluing (changing rankings for) pages in particular.
I've looked at my site as well as others for which I have stats. Every page on an affected site moved down, but some moved down a little, and some moved down a lot. For example, moving from #4 to #12 while another page moved from #5 to #49.
There are pages that dropped eight spots that seem to be as strong as the pages that dropped 44 spots. There's other factors that play into the difference in the levels of drop, though. I'm seeing some of those factors, but I need to dig deeper to find more.