This study investigates the effects of users' visualization ability and Web site structure display design on users' performance and memory organization in Web site information search tasks using a browsing strategy. A human-centered design-structure preview-was proposed in this study. Structure preview is a Web site navigation menu in which each menu item serves as a link to one Web page, similar to a menu design in Microsoft Windows 95 and Windows 98. An experiment was conducted in which 40 individuals participated. The experimental design was a 2-factor factorial design. Independent variables were visualization ability (low and high) and Web site design (conventional and structure preview). Twenty participants were identified as users with low visualization ability and 20 participants were identified as users with high visualization ability. Dependent variables were the number of identified items, the number of steps per item, and memory organization. Results indicated that both low- and high-visualization users' performance improved significantly (76.3% more identified items and 83.4% fewer steps per item for low-visualization users; 36.5% more identified items and 78.4% fewer steps per item for high-visualization users) when using the structure preview design than when using the conventional design. When using the conventional design, high-visualization users had significantly better performance (36.9% more identified items and 23.6% fewer steps per item) than low-visualization users. Also, the memory organization of all users (including both low- and high-visualization users) improved significantly (42.9%) when using the structure preview design compared with the conventional design.