One of the most pressing usability issues in the design of web sites is that of how to improve navigation and search. We are conducting a series of usability studies to address this problem, focusing on web sites that consist of large collections of loosely organized information. This article describes our method and presents preliminary results which suggest that use of faceted metadata can be useful both for the initial stages of highly constrained search and for the intermediate stages of less constrained browsing tasks. We also find that users state an interest in using different search interface types to support different search strategies.