Digital library resources as a basis for collaborative work

The creation of large, networked, digital document resources has greatly fa cilitated information access and dissemination, We suggest that such resour ces can further enhance how we work with information, namely, that they can provide a substrate that supports collaborative work. We focus on one form of collaboration, annotation, by which we mean any of an open-ended number of creative document manipulations that are useful to record and to share with others. Widespread digital document dissemination required technologic al enablers, such as web clients and servers. The resulting infrastructure is one in which information may be widely shared by individuals across admi nistrative boundaries. To achieve the same ubiquitous availability for anno tation requires providing support for spontaneous collaboration, that is, f or collaboration across administrative boundaries without significant prior agreements. Annotation is not more commonplace, we suggest, because the te chnological needs of spontaneous collaboration are challenging. We have dev eloped a document model, called multivalent documents, which provides a mea ns to address these challenges. In the multivalent document model, a docume nt comprises distributed data and program resources, called layers and beha viors, respectively. Because most document functionality is implemented by behaviors, the model is highly extensible, and can accommodate both new doc ument formats and novel forms of functionality. Among other applications, i t is possible to use the model to effect a wide class of annotation types, across different document formats, without any administrative provisions. A n implementation of the model has allowed us to develop behaviors that curr ently support some quite different but common digital document types, and a number of quite different annotation capabilities-some familiar, and some novel. A related implementation provides some analogous capabilities for ge ographic data. Such capabilities could have a beneficial impact on the "sch olarly information life cycle," i.e., the process by which researchers and scholars create, disseminate, and use knowledge.