Abstract: The invention relates to a method of limiting the number of simultaneous conversations in an instant messaging service comprising a plurality of instant messaging clients connected to an instant messaging server. Each instant messaging client has a presence status that can be seen by the other instant messaging clients in its own contacts list, said presence status varying at least between “Available” and “Busy”. According to the invention, when the number of simultaneous conversations for an instant messaging client reaches a predetermined number, said instant messaging client is seen as “Busy” for all the instant messaging clients in its own contacts list, other than those already in conversation therewith.