While users disseminate various information in the open and widely distributed environment of the Semantic Web, determination of who shares access to particular information is at the center of looming privacy concerns. We propose a realworld-oriented information sharing system that uses social networks. The system automatically obtains users’ social relationships by mining various external sources. It also enables users to analyze their social networks to provide awareness of the information dissemination process. Users can determine who has access to particular information based on the social relationships and network analysis. Categories and Subject Descriptors H.5.3 [Information Interfaces AND Presentation]: Group and Organizational Interfaces—collaborative computing, computer-supported cooperative work, web-based interaction General Terms Design, Human Factors Keywords Information sharing, Social network