Actually - I found the answer... it looks like the real impact was lowering the quantified estimates so that they are more in-line with the non-quantified. They basically trimmed their cookie estimates. Definitely makes it more of an apples-to-apples approach then, so I guess I'll quit badgering the other sites to get quantified!
From the Quantcast Website:
My position in Quantcast's Media Planner tool has changed - reported audience counts have decreased and resulted in a lower ranking. Why is this?
Prior to June 23rd, 2008, quantified publisher traffic counts in our Quantcast Media Planner tool were cookie-based.Non-quantified publishers had, and continue to have, people-based traffic estimates reported. In order to provide the marketplace with the best possible evaluation tool for understanding audiences, we have migrated all quantified publisher traffic counts to a people-based default. As our
Cookie Corrected Audience White Paper explains, cookie counts typically overestimate the actual number of people visiting a web property. Primarily for these reasons, your traffic counts and ranks have changed. It is important to note that our new estimates are more comprehensive, and representative of actual people-based data. This should help you in your ad sales, and revenue generation activities.
