Are You Using the Google Browser Size Tool?
Located in Google Labs:
How it Works from Google:
the FreeSeoReport.com folks yabbing about it (who BTW bought the site from Shoemoney?):
Page Layout Algo: Are You “Ad Stuffing”? - Blog - FreeSEOReport.com
What I can't tell of course from these links is how much content is good/ok/bad....
I have found about the web that the double large squares at the top of site posts has been penalized recently...most commonly used in the CTR Theme that if I remember right was recently up for sale on Flippa...
Supposedly the Ad part of the Google Algorithm isn't like Panda (ie updates more frequently), so more direct gratification from layout testing is theoretically possible...