Providing a new contents delivery method that is suitable for community networks and reduces leaks of personal information. Presentities indicating channels for information delivery are formed on presence service, and virtual channel communication terminals corresponding to their presentities are logically formed on an information delivery server. Thereby, contents are transmitted and received between the information delivery server and user communication terminals, and among the user communication terminals as if the contents were transmitted and received between a presentity indicating a channel and a presentity indicating a user. During contents transmission and reception, the need to exchange address information among users is eliminated, making it possible to prevent leaks of personal information.