11. One or more non-transitory computer-readable tangible media encoding software operable when executed to: access a record stored in one or more tangible media, the record recording a plurality of clusters of a plurality of documents, a document comprising a plurality of words, a cluster comprising a plurality of satisfactorily affine words of the plurality of words, a cluster indicating a theme; establish a number of themes of each document of at least a subset of the plurality of documents; determine a specificity of the each document according to the number of themes by: determining that the each document is more specific if the each document has a lower number of themes; and determining that the each document is less specific if the each document has a higher number of themes; receive a search query comprising a document specificity request, the document specificity indicated using a slider; and retrieve one or more documents of the plurality of documents that satisfy the search query and the document specificity request.
12. The computer-readable tangible media of claim 11 , further operable to establish the number of themes of the each document of at least the subset of the plurality of documents by: determining a number of clusters of the each document; and calculating the number of themes of the each document from the number of clusters.