An information processing method performed by a server includes receiving a request to initiate communication over an instant messaging system based on a connected voice call of a terminal, the request including a telephone number of the terminal, determining whether a particular user identifier of a user of the terminal is stored in a memory of the server based on the telephone number, the memory of the server storing one or more user identifiers in association with one or more telephone numbers, the one or more user identifiers being associated with the instant messaging system, and sending a message to the terminal based on the particular user identifier in response to determining the particular user identifier is stored in the memory.