An apparatus for processing messages input from a plurality of clients. The apparatus includes an acquisition unit configured to obtain a first message input from a first client, a second message input from a second client, and a user selection input from the second client. The user selection is of a first portion of the first message and indicates that the second message is a comment on the first portion of the first message. The apparatus also includes a control unit in communication with the acquisition unit. The control unit is configured to perform a first control action in response to the acquisition unit obtaining the first message, the second message, and the user selection. The first control action results in the first message, the second message, and a first link connecting the first portion of the first message and the second message being displayed on the plurality of clients.