[anyzen]

Am I missing something? Google gives me the creeps as much as it does to any sane person, but if I understand correctly, DDG is comparing just the variation of results on each page. This doesn't mean that you're still in the (same) bubble when you log out.

How about comparing the logged-in data with logged-out / private tab data? Did they find these two sets related? If not, G could be just implementing some sort of A/B testing on grand scale (learning from clicks and making search algorithm better).