Weblog has quickly evolved into a new information and knowledge dissemination channel. Yet it is not easy to discover weblog communities through keyword search. The main contribution of this paper is the study of weblog communities from the perspective of social network analysis. We proposed a new way of collecting and preparing data for weblog community discovery. The data collection stage focuses on gaining knowledge of the strength of social ties between weblogs. The strength of social ties and the clustering feature of social network guided the discovery of weblog communities. Categories and Subject Descriptors H.3.3 [Information Search and Retrieval]: Clustering and Retrieval models. General Terms Algorithms, Experimentation, Keywords Weblog, Community, Social Network, Social tie