Patent ID: 6980792

Claim:
A method for billing a sender of a message for a reply to the message, the method comprising: creating a first message; adding to the first message a first indication indicating at least to a message transmitting system that a sender of the first message is billed for a reply message to the first message; giving a time limit to the first indication, the time limit indicating how long the first indication is valid; transmitting the first message containing the first indication to a receiver; and when the receiver replies by reply message to the first message: adding a second indication to the reply message, the second indication containing at least a part of the first indication and indicating to the message transmitting system that this reply message is a reply to the first message; checking, in response to the second indication, whether the first indication is still valid; and billing the sender of the first message for the reply message on the basis of the second indication only if the first indication is still valid.