关键词: 复杂网络, 社区结构, 聚类, 社会网络

Abstract: User-oriented online sharing communities have been development growth recently.The characteristics of these communities set them apart from traditional online message-based communities.This research constructs the user network using data collected from an IRC music channel from 2001 to 2006.After a series of measurements of the network，the authors represent the directed network as bipartite network.And then the authors detect the community structure by hierarchical clustering.According to the experiment result，the authors make an analysis of the shape，size and distribution of the community.Finally，the authors propose some approaches to enhance the net service.

Key words: complex network, community structure, clustering, social network