I'm reminded of User Testing at Powerset. When we did unbranded search testing of Wikipedia, late-stage Powerset usually won most search comparisons by users. But if we branded the search results against Google, we lost. At first we thought this was an artifact of the test data, but then we ran an experiment where we randomly assigned a brand to our search results and asked users to rank them. Same GvP comparison. The Google branding won. We took it a step further: sometimes random recall searches crept in (there aas essentially no logic to what we put in front of the users other than keyword match). If those got branded "Google", sometimes they still won just by the power of brand association, even against Powerset's sophisticated NL-powered search.