Navigable history: a reader's view of writer's time

Abstract Collecting, analyzing, and sharing information via a hypertext results in the continuous modification of information content over a long period of time. Such tasks will benefit from users having access to this authoring process. The Visual Knowledge Builder (VKB), a spatial hypertext system designed to support collaborative knowledge building, includes navigable history to provide readers a view of the writer's time. VKB acts as a workspace for collecting, organizing, and interpreting information in a hierarchy of two-dimensional planes. During authoring, VKB records events in the hypertext's history and provides methods to access prior states of the hypertext. The reader may play forward or backward through the authoring process as well as search for a variety of authoring events on information objects. Users receive cues about the absolute and relative timelines of the information space through the presentation of information about specific events and their sequence. Examples of VKB's use include note taking, writing, organizing conferences, and sharing information in a research group. Analysis of VKB workspaces in these contexts indicates navigable history supports 1) learning and interpreting authors’ work practices, 2) recognizing patterns of activity in the information space, and 3) disambiguating specific actions and content. Hypertexts that include an authoring history add a notion of constructive time for their readers.