kd454 - 4:20 am on Mar 8, 2011 (gmt 0)
"Has anyone else noticed the trend that sites which rank well now seem to have their ad blocks outside the primary content area (e.g. headers, sidebars, footer, etc..)?"
If you look at the sites on Webmaster Central that are listed and all the content farms, seems the amount of ads and placement play a BIG role in the trigger, ads above fold, in-content ads the more you have the bigger the hit.
Google Adsense reps advise you to put more ads in those areas and Google search quality team nails your site for it - this it enough to make your head spin.
I just received an email yesterday for another one on one with an Adsense rep, I am going to start removing ads not put more.