I was thinking about Panda today, and about the Google Supplemental Index. It used to be really popular to check which of your results were in supplemental due to the little green tag that appeared next to a result.
I hear that Google still has this index, it's just not made clear to us which url is or isn't in supplemental.
I wonder if Panda's rank drops across sites were it simply putting them into the supplemental index. When someone regains rank, it's because their site comes out of supplemental.
I can't find a solid way of determining if a url is in the supplemental index... anyone have a way?
When Google stopped labeling Supplemental Results, my understanding was that their technology was changing to the point where there would be MANY database "partitions", not just two. And then when Caffeine took over from Big Daddy, Google's underlying infrastructure changed even further and quite dramatically.
There are hacks that people used to use - site:example.com/* and variations - and they were thought to generate a supplemental count. This past year Matt Cutts commented on those hacks that they never showed the supplemental count, but instead tripped an error routine that caused the full site: operator calculation to stop short.
So as intriguing as your idea is, given the above I don't think Panda works like that. I think it generates an actual quality score (negative or positive) that is stored separately for both pages and sites. That score is then combined with the rest of the ranking algorithm to generate final results.