In spite of the radical enhancement of web technologies, many users still continue to experience severe difficulties in navigating web systems. One way to reduce the navigation difficulties is to provide context information that explains the current situation of users in the web systems. In this study, we empirically examined the effects of two types of context information, namely, structural and temporal context. In the experiment, we evaluated the effectiveness of the contextual navigation aids in two different types of web systems: an electronic commerce system and a content dissemination system. In our experiment, subjects performed several browsing tasks and answered a set of post-questionnaires. The results of the experiment reveal that the two types of contextual navigation aids significantly improved the performance of browsing tasks regardless of different web systems. Moreover, context information changed the users' navigation patterns, and increased their subjective ease of navigation. This study concludes with implications for understanding the users' browsing patterns and for developing effective navigation systems. Copyright ACM 2000.