zjacob - 2:35 am on Oct 9, 2007 (gmt 0)

Apart from all the other speculation of what is going on with the serps, my observations would suggest that there are things going on that go beyond traditional SEO.

Rather, much of the changes in the serps would suggest that Google is weighting more heavily SERP CTR rates and bounce-back rates from those clicks, similarly to what they've been doing more and more with Adwords in determining a Quality Score.

Maybe their new garbage identifying mechanism weights more heavily this "Quality Score" of your SERP listing?