Web_speed - 8:22 pm on Mar 3, 2012 (gmt 0)
Whatever the reason, the engineers at google are seeing the same garbage that many of us are. They are aware of those huge swings in conversions and traffic quality. I think it has just spun out of control and they are just lost.
I think you are spot on!
These no longer look like "updates" or "data refreshes". They look more like a pathetic attempt at making a flawed algo stick. They are well and truly lost.