Hypermedia is highly appropriate for collaborative work. In addition to being used as a tool for idea processing, NoteCards has been used for collaborative writing. Since this activity can be highly coupled and unstructured, hypermedia is the most appropriate technology to represent both the work and the discussion about the work (meta-discussion) and about sharing the medium [Irish & Trigg, 1990]. Also, the rationale for decisions made during the writing activity can be preserved for historical purposes. NoteCards provided the environment for people to capture, structure, compare, and manage large amounts of loosely structured textual, graphical, and numerical information. In order to support the social interactions inherent in collaborative work and shared access to networks of information, NoteCards required multi-user access and concurrency control mechanisms, and version control. Irish and Trigg state that hypermedia is a good medium for supporting meta-discussions for the following reasons:
From a Computer Mediated Communications (CMC) point of view, hypertext can be "viewed as a mechanism to enable an individual to impose a cognitive viewpoint on a collaborative database, and to facilitate group agreement on a shared understanding of the resulting semantics." [Turoff et al., 1991]. In a group project, each member of the team is working towards a sub-goal which forms part of a larger objective for the organization. Such an environment requires tracking, linking, and reorganization of information related to various sub-goals and the main goal itself. It can be argued that every CMC system capable of mail, conferences, comments, replies, and notifications can be viewed as a variation of the hypertext concept. For example, in EIES2, the facilities to reply to a mail item or add an attachment which form branches to the original piece of material can be considered a hypertext feature. The ability to cross-reference through keywords, and associated comments can be considered another hypertext feature.
Turoff et al., extend the general framework for hypertext functionality (covered in Chapter 6), to include a general morphology of terms for node and link types. Such a general approach allows users of a system to freely assign their own semantics to objects and relationships. The semantic model for hypertext-based collaborative systems should support the full range of human intellectual abilities. That is, such a system should allow any group member to define and describe objects (nodes) and relationships (links) between objects incorporating the full range of possible meanings for those nodes and links. Collaborative hypertext should also provide information about the composition or evolution process, the way the network is dynamically changing. This can be achieved by creating a "group memory" where nodes and links created during the collaborative process can be accumulated. Collaborative hypertext systems should support "collaborative intelligence where the group can obtain a far more intelligent result than the most intelligent member would have acting alone." [Turoff et al., 1991].
An application called InterNote has been implemented in the Intermedia framework to support annotative collaboration [Catlin et al., 1989]. The annotative collaboration process involves commenting, questioning and critiquing others' work. In addition, these notes or annotations can be assimilated back into the original document to create a new and improved version of the document. The facility to incorporate annotations into the original document, resulting in data transfer across the annotation link, is called warm linking. The system also supports annotation management, simultaneous multi-user annotation, and contention management.
The Virtual Notebook System (VNS) is a collaborative environment for scientific groups engaged in basic and clinical research in an academic medical center [Shipman III et al., 1989]. This system supports information acquisition, information linking and sharing, and information management in a group environment. It is capable of maintaining information about hypotheses, notes, and other relevant information which can be shared with other researchers located at remote sites. The system has facilities to import information from external sources such as electronic mail, USENET bulletin boards, bibliographic services, genetic sequencing information, and clinical databases.
Researchers who developed ABC, a hypermedia system for Artifact-Based Collaboration, consider the output of a group problem-solving process as an artifact [Smith & Smith, 1991]. For example, in the software development process, the artifact consists of concept papers, architecture, requirements, design specifications, programs, diagrams, references, and user manuals. The system can manage source code trees (as hypertext graphs), decomposition diagrams, call-flow diagrams, and uses-hierarchy diagrams. ABC contains six key components - a graph server, a set of graph browsers, a set of application programs, a shared window conferencing facility for synchronous and asynchronous communications, real-time audio and video, and a set of protocol tools to study group behavior and strategies.