28. The system of claim 26 , wherein comparing the characteristics of the preexisting structured presentation with the content of the electronic documents comprises identifying documents in the electronic document collection that include information regarding one or more instances in the preexisting structured presentation.
26. A system comprising: a client device comprising a display screen; and one or more computers programmed to interact with the client device and to perform operations comprising: receiving description data describing a preexisting structured presentation, a visual presentation of the preexisting structured presentation visually presenting information in a systematic arrangement that conforms with a structured design, the preexisting structured presentation including values that each characterize a respective attribute of an instance, the preexisting structured presentation denoting characterization of attributes of a particular instance by particular values by virtue of an arrangement of an identifier of the particular instance and the particular values in a visual presentation of the preexisting structured presentation; conducting, by the machine, a search of an unstructured collection of electronic documents by 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 in response to the locating of the electronic documents an identifier of the new attribute to the preexisting structured presentation to form an expanded structured presentation, wherein adding the identifier of the new attribute comprises: formulating a collection of attribute suggestions, wherein formulating the collection of attribute suggestions comprises: identifying a first document in the electronic document collection that is relevant to one of the instances identified in the preexisting structured presentation and that is arranged in accordance with a template, where the template is a pattern for the arrangement of the content of the first document; and adding an attribute used in the first document to characterize the instance in the attribute suggestion collection; providing the attribute suggestion collection to a user; and receiving a user selection of the new attribute, wherein the new attribute is in the collection of attribute suggestions; and outputting instructions for presenting the expanded structured presentation on the display screen.