Panda is an algo run on more active sites (sites that publish fresh content on a regular basis) which get some decent traffic for some decent keywords.
I find that really interesting. Our site saw a substantial decrease in qualified traffic right around Panda 1, but only our high quality pages took a hit.
Our crappy low-quality templated content still ranks as high as ever (even though we receive virtually no traffic from it). It's as if all those pages are still living in a pre-panda world. I guess I don't understand Google's logic there - leave the cancer but destroy the healthy cells?
When Panda was released, Google claimed that it only affected 12% of search results in the US - I wonder what percent of actual searches Panda affected.