Think travelincat has hit the right spot here. I've been lurking this forum on and off - at times when Google acted up. This week i had a look again, because Google SERPS are well off mark.
It strikes me discussions are pretty much the same each time i have a look. Google demotes sites during Algo updates, publishers go crazy about lost rankings / revenue.
The Panda thing seems like a bigger change, but the web has grown bigger and more are in the worldwide sport of Google Algo manipulation. Any algo update from google just hits more out there.
The discussion about the Free Traffic part is interesting. With 90% market domination / dictatorship, the inevitable will happen some day - Google gets less big. Because people start using other search engines to find what they want.
Just the word has to spread and "free traffic" will appear elsewhere. Bing or whatever other SE gets bigger and bigger and starts updating Algo's also.
There was an article a week ago about online newspaper sites getting demoted big time - content versus adspace made Google demote them like spamsites.
Manual intervention was necessary to put them back into the top rankings .... because "Free Traffic" was lost and Ad revenue dropped like crazy.