A client subscribes to a pub/sub service, the client comprises an application program for performing an operation on a published message received from a Pub/Sub service. The operation on the message comprises any one of saving the message to storage, accessing a web service based on information in the received message, authorizing subscription, executing an application identified by the message, filtering the message information for presentation to a user, overriding a message function, transforming the message media format or forwarding the message to another node.