Information is quickly offered to users who require the information. In a system in which questions and answers are exchanged, when a given user other than the questioner becomes interested in a question, the user requests a notification server 1 to present the question. The answers to the question are automatically sent to a notification client 2 of the user. The answers to be sent may be either all the answers to the question or only the effective answers. Supports to the answers and comments on the answers may be accepted to decide the effectiveness of the answers.
