indyank - 2:35 am on Oct 16, 2011 (gmt 0) [edited by: indyank at 2:39 am (utc) on Oct 16, 2011]
I'm guessing here, but major keywords, plus perhaps top 20 of others. So every time Panda demotes stuff, new dross that wasn't assessed surfaces.
I had always been saying that keywords are the basic unit used to determine the SERPS for Panda to act upon.
I don't think they would run this on a daily basis in the near future. They might never do that. As it stands now, they don't even evaluate a complete site and it is only a certain percentage of pages which are pushed into the Panda machine to arrive at a score that is then applied site wide.
As long as this continues (and I don't see this changing any time), you will continue to see "popular" + "dross" on top.
[edited by: indyank at 2:39 am (utc) on Oct 16, 2011]