Portable browsing interface for information retrieval

An integrated searching/browsing mechanism employs user-constructed information hierarchies that represent a cognitive framework for the organization of information. The hierarchies are independent of the information itself. This feature permits them to be shared among multiple users, and applied to any of a variety of different sources of information. The hierarchical organization that is provided by the framework gives the user the ability to browse around any available document database in a manner that is intuitive to the user. Two or more hierarchies can be combined to locate documents which match the criteria of both hierarchies, and thereby refine search results to an appropriate level. A relevance feedback mechanism further enhances the browsing experience, by concentrating the search results in areas that are most relevant to documents selected as being of particular interest.