According to one embodiment, there is provided a control block including a read control processor for reading designated content, a time information processor for processing time information. A controller returns, to a user terminal, a response signal, and information indicating a second absolute time point when an operation is executed in response to a request signal generated by the user terminal at a first absolute time point. The controller stores time difference information indicating a time difference between the first and the second absolute time points. When responding to a further request signal sent from the requester via the network, the controller sets, as tag time information, time information obtained by correcting, using the time difference information, a current relative time period for which the designated content is read.