When people have meetings or discussions, frequently they use conversational props : physical models, drawings, or other concrete representations of information used to enhance the exchange of information. If the participants are geographically separated, it is difficult to make effective use of props since each physical prop can only exist in one place. Computer applications that allow two or more users to simultaneously view and manipulate the same data can be used to augment human-to-human telecommunication. We have built the Rendezvous system is similar to many UIMSs or user interface toolkits in that it is intended to simplify the construction of graphical direct-manipulation interfaces. It goes beyond these systems by adding functionality to support the construction of multiuser applications. Based on experience with several large applications built with the Rendezvous system, we believe that it is useful for building conversational props and other computer-supported cooperative work (CSCW) applications. We present a list of required features of conversational props, some example applications built with the Rendezvous system, and a description of the Rendezvous system.

Our work focuses on providing computational support for informal communication among people who are geographically separated. To better understand the use of artifacts in communication, we looked at the contents of office whiteboards after they had been used in conversations. Our analysis revealed that whiteboards are used to present and discuss various classes of objects with specific semantic properties. We call these objects "conversational props," and we have come to think of a whiteboard as a conversational medium in which props are introduced and manipulated. This study motivated our design of the Conversation Board, an experimental prototype of a multi-user drawing tool which allows remote use of conversational props. We compare the Conversation Board to various other multi-user drawing tools along a number of dimensions.