I don't think even the Freakonomics followup is valid because there's a huge difference between telling someone to run some searches and actual search engine use. Here's what I might type if someone asked me to try their search engine: "Miley Cyrus". The funny thing is that I'm not sure if I would like Google's "Miley Cyrus" results better than Bing's. I'm not sure I could tell the difference. Here's the kind of stuf…
It would be like finding out olympic class weight lifters tend to also be olympic class marathon runners. Or the best commuter vehicle and best 100 ton mining truck happen to be the same vehicle.