I hope MHs example stays. It illustrates what I'm seeing. Google has blown semantic understanding of what sites are about. They are doing it now with ours thinking we ARE the manufacturer sending us competitors instead of customers when we make it explicitly clear.
So our traffic is up 45% but it's all garbage. All we've gotten for two or three days is people complaining about the manufacturer thinking we are them. much like the world history example google misunderstood our site which is shocking as they can clearly see when they send the right traffic we convert at 25%.