US Patent 8250206 Communication control

A server including a storage unit for storing a history of activities that each character in a virtual world has performed; a search unit for searching the storage unit to retrieve a history of activities in which a first character that performs an activity on a first client has changed the states of a second client that performs an activity on a second client; a calculation unit for calculating, on the basis of the retrieved history, a score indicating the extent to which the first character has changed the state of the second character; and a transmission control unit for controlling the frequency with which the states of the first character are changed according to an operation performed by a user on the first client.