In this paper, we investigate the effectiveness of the system design of a Web information analysis for open-domain decision support. In order to make decisions, it is required to collect and compare information from various view points. In case of making decisions based on Web information, however, it is difficult to obtain diverse information from variety of sources by using current search engines. Based on this observation, we design a system for supporting open-domain decision making, which analyzes Web information. Among the major design decisions are to focus on two elements, i.e. identifying the source of information and the extraction of informative content, and to organize the two elements so that the user can quickly grasp who is saying what on the Web. The assumption behind such decisions is that information organized in such a way would facilitate proper judgments in the user's decision making process. We conduct users evaluation to verify the effectiveness of our approach. In the result, it is confirmed that our system is superior to current search engine for grasping organized information from different stance of senders and supports the process of decision making, by (i) uncovering biases, (ii) showing various opinions from multiple view points, (iii) revealing information sources.