1. A method of controlling a number of object update requests sent from a client system to an application server, the method comprising the steps of: receiving a request in a polling server from a client system, the request including data identifying a first user and an object provided to the client system by an application server; determining in the polling server whether an update message related to the object has been received by the polling server from the application server; and if so sending a response from the polling server to the client system, the response including information usable by the client system to determine if new or updated information related to the object is available on the application server; and receiving at the application server an update request from the client system responsive to the client system processing the response to determine that new or updated information related to the object is available on the application server.