While items in a collection may vary greatly, we will assume that a superset of attributes exist for all the items. Attributes may be blank, have single values, multiple values, or they may be a lengthy text. Typically a collection is owned by a single library, and an item belongs to a single collection, although exceptions are possible. A multimedia document library consists of collections of documents in which the documents can contain images, sound, video, animations, etc. Task actions are represented by interface actions such as browsing, searching, joining, or linking.
Users begin by formulating their information needs in the task domain.
The conversion of information needs, stated in task domain terminology, to interface actions is a large cognitive step, but it must be accomplished before expression of these actions in a query language or series of mouse selections can begin. Supplemental finding aids can help users clarify and pursue their information needs. Careful understanding of previous and potential search requests, the task analysis, can improve search results by offering hot topic lists and useful classification schemes. For example, the Congressional Research Service has a list of approximately 80 hot topics covering current bills before Congress and 5000 terms in their Legislative Indexing Vocabulary.