We saw some usability footage the other day for our new website. We asked some undergraduates to find a book on x topic. A librarian of course would immediately go search the OPAC by keyword or subject. What did one of the undergraduate do? Go search the subject in wikipedia and scroll to the end of the section looking at the references. When the references turned out to be only articles and not books, they just jumped over to Amazon. Not only were they able to find books over there, they could read a review which helped them choose one book. And then and only then, did they go to the OPAC to find the call number.