“With Web search engines don’t we have access to enormous numbers of users searching the same corpus?” [SG] Yes and no. The Web generally–and Web engines in particular–obviously generates huge traffic and potentially much interesting data about how real people (versus experiment subjects) FOA. But access to these statistics, most conveniently collected by Web search servers, is an increasingly valuable commodity! Many people would like to know what sorts of things people are searching for and how they search for it. It’s also important not to think of the Web that everyone is searching as “the same corpus.” One of the Web’s most salient features is its dynamism. New documents are added and others (or at least the links to them!) are removed all the time. This makes comparing search retrieval results at two different times difficult.