A communication system includes a community management server used by a communication manager and a participant's terminal used by a community participant participating in communication. The community management server manages multimedia data that has data about the community participant embedded therein, an element symbolizing the community participant, a data content display control part and a participant personal identification authentication part. The participant's terminal includes generation part for generating card-like information as a communication unit. When a plurality of community participants executes communication by using the cards to which the multimedia data are put, they can execute information display of personal information of the community participants, authentication of personal identification, and retrieval/edition of a speech content by using information embedded in the multimedia data.