1. A machine-implemented method comprising: receiving description data describing a preexisting structured presentation, a visual presentation of the preexisting structured presentation visually presenting information in an systematic arrangement that conforms with a structured design, the structured presentation denoting associations between an instance and values that characterize attributes of the instance by virtue of an arrangement of an identifier of the instance and the values in a visual presentation of the structured presentation; comparing characteristics of the preexisting structured presentation with content of electronic documents in an unstructured collection of electronic documents to locate electronic documents that identify a new attribute that is relevant to the preexisting structured presentation; adding an identifier of the new attribute to the preexisting structured presentation to form an expanded structured presentation; and outputting instructions for presenting the expanded structured presentation on a display screen.