It's mentioned earlier in the thread by me, tedster, and Cain.
I think we were also the main 3 who followed, noticed, and/or correctly diagnosed the Position #6 issue last year [webmasterworld.com].
We all also noticed that this rollout has been remarkably similar
(even to the "authority" sites being affected most)
It's hard to explain without rehashing all my rants about how the Position #6 [webmasterworld.com] roll out originally
(which I'm sure tedster is tired off) =P