1script - 3:57 pm on Aug 7, 2012 (gmt 0)
I thought of that and I do, in fact, catch quite a few rogue robots trying to appear as if they came from Google on very bizarre keywords, something I would never be ranking on and can't find my site anywhere on that SERP when checked. But the amount is not all that significant compared to the normal Google traffic. Also, some of the competitors are checking up on me automatically and their software appears to have google.com setup as the referrer.
What if these visitors weren't people? What if they were bots or something like that?
So, I guess, it is a valid idea but it cannot account for the significant difference in engagement. Besides, for the total traffic to be stable, the robot attack would have to be timed perfectly with the dip in real Google traffic - I don't see even a remote possibility of that.
I can't see how anyone would benefit from that either. Perhaps I'm just not feeling particularly imaginative today ...
By the way: the Search Queries report in WMT hasn't been updated in 6 days now - this is very peculiar. Calm before a storm?