walkman - 9:53 am on Jun 14, 2011 (gmt 0)
"Suppose two blocks of ads caused your site to tip the scale to PandaLand"
I was at the Oxford Adsense road show and on the question about adds and the Panda update, the answer was that add placement has nothing to do with the recent update as long as the page is user friendly and has original content, not just a few words and a bunch of adds.
First, I used that as an example to see if Goog responded to changes. But ads can make a site non-user friendly so I would ignore the above advice. What one person said once, might not no longer be valid.