A Danish ad company made a Google interface that they called "impersonal me" which searched Google with no personalisation. And not only was it better than Google search, it found things that normal Google just didn't show. In particular old comments I had written and lost track of. In the impersonal search they were easily found, in the normal search they weren't way down on the list, they weren't in the list at all.

Fascinatingly bad.