Social networks are important for the Semantic Web. Several means can be used to obtain social networks: using social networking services, aggregating Friend of a Friend (FOAF) documents, mining text information on the Web or in e-mail messages, and observing face-to-face communication using sensors. Integrating multiple social networks is a key issue for further utilization of social networks in the Semantic Web. This paper describes our attempt to extract, analyze and integrate multiple social networks from the same community: user-registered knows networks, web-mined collaborator networks, and face-to-face meets networks. We operated a social network-based community support system called Polyphonet at the 17th, 18th and 19th Annual Conferences of the Japan Society of Artificial Intelligence (JSAI2003, JSAI2004, and JSAI2005) and at The International Conference on Ubiquitous Computing (UbiComp 2005). Multiple social networks were obtained and analyzed. We discuss the integration of multiple networks based on the analyses.