In a colloboration system which allows a plurality of programs to interact, each program registers an "interest" in messages with a session object. The session object, which represents the colloboration session and acts as a collaboration manager, receives all messages but broadcasts a received message only to those programs which have registered an interest in the message. In one embodiment, a colloborative application framework is used to build both the session object and the application programs. The framework includes class code information which is incorporated into each application program by subclassing and which allows each program to communicate with the session object through a predetermined protocol.