Arguably, usability testing is most effective when integrated into the user-centered design process. One way to encourage this integration is to reemphasize the value of paper prototyping. In a recent test of a university library website, we married low-fidelity paper prototyping with medium-fidelity wireframe prototyping. When user navigation led to nonexisting pages or dead ends, users were encouraged to create what they thought should be where there was nothing. This blank-page technique gave us insights into users' mental models regarding site content and design, providing developers with useful data concerning how users conceptualized information they encountered.