The User Interface 

User interfaces are mechanisms built into information systems and services to enable the users to utilise these services in an effective manner. The interface is an obvious factor in bibliographic on-line searching systems, and Value Added On-line Systems (VAOLS). Value may be said to be added in any of the areas of input, retrieval, manipulation and output, that is, at any point which affects the user. Usually, added value is claimed on the basis of either ease of retrieval, or facilities provided for dealing with the information retrieval: processing, analysis and other forms of manipulation and presentation.