A case study of the design of large-scale communityware called Public Opinion Channel (POC) in a field-test is described. POC is a notion of a community broadcasting system that facilitates community members to exchange their opinions. We report (1) design issue of the POC, and (2) community management and analysis issue in the field-test to which about 450 households attend. In the design issue, we describe details on data structure, architecture, and protocols of the POC. In the management and analysis issue, we describe engineering and human efforts to prepare log analysis tools, initial contents, and a regulation.