I didn't even know something like this was going on nor do I know what Panda, Penguin mean in relation to the web. I have not checked my serps in ages but I checked now and they seem to be the same or a little better than in the past. Are the ones who get hit the most linking like hell to the main page and not enough to interior pages, long tail keywords etc? Seems like that may be the case. Does this have anything to do with duplicate content?