Based on the work of Fridael [1993], Meijer [1994], and Rodden [1991], I identify four classes of CSCW systems that have emerged over the last decade:
Without a doubt, electronic mail or e-mail systems are the most successful and mature form of groupware. Electronic mail originally emerged as a substitute for traditional mail (nowadays often referred to as 'snail mail'). In the early days, textual messages were directed at a single individual or at a small number of individuals. As the development and use of local and wide area networks (LAN and WAN) grew rapidly, this form of computer-mediated communication became more widespread. Also, the complexity and functionality of these systems has quickly increased. As will be shown in the section on effects of CSCW, the impact of electronic mail systems on individuals, groups, and organisations was large.
Typically, message systems are used for asynchronous and remote interaction. In order to support cooperative work, messages may be send to large numbers of individuals who belong to a certain group or who share a common interest. Mail systems may be divided into procedure based and non-procedure based systems. Non-procedure based are those classical mail systems which exchange free, usually text-based messages between group members. Message systems such as the The Coordinator (Flores et. al. [1988]) are fully procedure based because 'intelligence' is added to the message delivery system. The Coordinator interacts on the contents of the message. Scripts are another example of intelligence; these little programs can be attached to messages and execute in the receiver's environment. The sender can, for instance, query the receiver without him noticing or he may automatically re-route the receiver's reply on a message (Fridael[1993]).
Conferencing systems are related to electronic mail systems. However, conferencing systems differ from message systems in that structure is imposed in terms of how messages are grouped. On the one hand, further developments of electronic mail applications lead to the evolution of teleconferencing systems. Computer conferencing systems, or electronic bulletin boards, organise user access and message transmission by topic or by time rather than by the names of the individual recipients. Bulletin board messages are usually organised by time. Besides, the emphasis is on broadcasting information regarding a certain topic towards an interested community. This joint interest ties the group members together. Teleconferencing systems typically facilitate remote interaction between group members, in either synchronous or asynchronous modes.
On the other hand, growing interest in supporting group meetings has lead to the development of Group Decision Support Systems (GDSS) in general and automated meeting rooms or electronic meeting systems (EMS) in particular. Automated meeting rooms provide support for the exploration of unstructured problems in a group setting. The primary target is to improve the productivity of decision-making meetings, either by speeding up the decision-making process or by improving the quality of the resulting decisions. Meeting rooms are generally filled with various technological tours de force. They contain several networked workstations, large computer-controlled public displays that serve as electronic blackboards and additional audio/video equipment (Ellis et. al. [1991]). Examples are discussed by Nunamaker et. al. [1991].
Because every group member is present at the same time, communication in an EMS is synchronous. However, that does not mean that a group member cannot take part in the meeting when he is physically dispersed from the others. It is possible to establish a virtual meeting room, thus overcoming spatial constraints.
Coordination systems address the problem of integration and harmonious adjustment of individual's work efforts toward the accomplishment of a common goal. Examples of coordination systems include electronic calendars and automated meeting scheduling software. Coordination systems are liable to impose some rather heavy constraints on the people who use them. For example, in order for a system to automatically schedule a meeting it needs to know the private schedules of all people taking part in this meeting. Therefore, these systems are mainly used by managers and executives with personal secretaries who maintain their agendas. In contrast to other computer supported cooperative work systems, in coordination systems communication plays a minor part; it is less important than the envisioned goal of the system. Coordination systems are generally used in an asynchronous and remote way.
Co-authoring systems aim to support the cooperation necessary between co- authors in document production. In general, these systems support asynchronous cooperation with each group member working independently on a specific portion of the document. Reviews and comments may be added to the document later by annotating sections of it (Rodden [1991]). Co- authoring systems are not distinguished by the location of their users, who can be either remote or co-located.
Argumentation systems support the structured development of multiparty arguments and negotiations. A well known example is the gIBIS system which is described by Begeman and Conklin [1988]. Due to the many and very diverse activities that may be distinguished within a co-authoring environment, argumentation systems are useful additions to co-authoring systems.
The larger part of this work deals with the design and implementation of a co-authoring system, The COOPerator, at the Infolab at Tilburg University. Therefore, a closer look at co-authoring systems is provided.
Sjoerd Michels, Tilburg, The Netherlands