A computer system enabling mutual exchange of information between users and digital content, in a manner corresponding to each individual disk, comprises a plurality of computers each capable of being loaded with a disk having a unique disk ID, and a verification server capable of being connected with the computers via a network. Each disk has a unique ID, and the verification server has a user database for accumulating user information corresponding to the disk ID. The verification server identifies the disk based on the disk ID, and transmits data corresponding to the disk to the computer.