In what can only be considered a reaction to negative feedback on an AdWords System change Google reversed itself for the first time in my memory. Several days ago they announced that they were changing the ad rotation in an obvious move to enhance their profits and it appears that Google got an ear full of very negative feedback. This is actually encouraging since they often seem to be hard of hearing on these types of issues.
Here is the reversal posting http://adwords.blogspot.com/2012/06/update-to-recent-ad-rotation-change.html
Here is the initial posting http://adwords.blogspot.com/2012/04/new-changes-to-ad-rotation.html
Maybe this is a signal that the voice of the advertisers are important to Google when it comes from large crowds.