tedster - 11:16 pm on May 16, 2010 (gmt 0)

But what to study?

I'm starting out with the degree of churn. Which SERPs (which type of query terms) are churning and which seem relatively stable. Also which positions seem to be most involved in the churn. I'm hoping, with such data, that some further directions for investigation will become clear.

And I might not get anywhere - but it feels like an angle that might bear some fruit. Something more than historically acknowledged factors seems to be at work, now. If it is CTR (or even Site Performance) then the data for websites that I am not involved with will be hidden to me, so conclusions will be rather hard to come by. But I will give it a try.