I see this from time to time myself where someone points out how bad the results are, but different results for me when trying the example. However, there are certain other things that I have searched for myself that absolutely resulted in crap results from SEO/blogspam type of results. So I know 100% it happens.

What I'm wondering is how much of your recognized fingerprint influences the results? What causes results to be different from user to user using the same search query?