A management system for the exchange of messages each comprising an identifying part and a content part, comprising: at least one server overall comprising at least two boxes (6a, 6b) of messages each associated with a respective identification address; said server being designed to receive a first message from a first box and a second message from a second box; at least two client interfaces operatively connected to the server by means of a data exchange network and enabled to access the same box of the two boxes (6a, 6b) of messages by means of the server; each client interface being designed to read each message (2a, 2b) on the server; said management system being designed for: - detecting the identification information of each message (2a, 2b) representative of the identifying part of the respective message (2a, 2b); - comparing the identification information of the first message with the reception information of the second message; - if the identification information relating to the first message and to the second message matches, storing the content part of only one of the two messages (2a, 2b) on the server and making said content part stored accessible to each client interface by means of the data exchange network; each client interface being designed to access the same message on the server and to make it displayable to a user; characterized by said management system being designed for: associating with the message received on the server a memory register containing a plurality of data determined depending on the actions performed by each client interface on the message; making said memory register accessible to each client interface by means of the data exchange network; wherein said memory register containing for each client interface the data relating to the actions performed by the client interface on the message; and by each client interface being designed to: send a change signal indicating a change in a data item contained in the memory register to the server depending on the actions performed on the message; read the contents of the memory register and modify the contents. at least one server overall comprising at least two boxes (6a, 6b) of messages each associated with a respective identification address; said server being designed to receive a first message from a first box and a second message from a second box; at least two client interfaces operatively connected to the server by means of a data exchange network and enabled to access the same box of the two boxes (6a, 6b) of messages by means of the server; each client interface being designed to read each message (2a, 2b) on the server; said management system being designed for: - detecting the identification information of each message (2a, 2b) representative of the identifying part of the respective message (2a, 2b); - comparing the identification information of the first message with the reception information of the second message; - if the identification information relating to the first message and to the second message matches, storing the content part of only one of the two messages (2a, 2b) on the server and making said content part stored accessible to each client interface by means of the data exchange network; - detecting the identification information of each message (2a, 2b) representative of the identifying part of the respective message (2a, 2b); - comparing the identification information of the first message with the reception information of the second message; - if the identification information relating to the first message and to the second message matches, storing the content part of only one of the two messages (2a, 2b) on the server and making said content part stored accessible to each client interface by means of the data exchange network; each client interface being designed to access the same message on the server and to make it displayable to a user; characterized by said management system being designed for: associating with the message received on the server a memory register containing a plurality of data determined depending on the actions performed by each client interface on the message; making said memory register accessible to each client interface by means of the data exchange network; wherein said memory register containing for each client interface the data relating to the actions performed by the client interface on the message; and by each client interface being designed to: send a change signal indicating a change in a data item contained in the memory register to the server depending on the actions performed on the message; read the contents of the memory register and modify the contents. associating with the message received on the server a memory register containing a plurality of data determined depending on the actions performed by each client interface on the message; making said memory register accessible to each client interface by means of the data exchange network; wherein said memory register containing for each client interface the data relating to the actions performed by the client interface on the message; and by each client interface being designed to: send a change signal indicating a change in a data item contained in the memory register to the server depending on the actions performed on the message; read the contents of the memory register and modify the contents.