1. One or more tangible computer-readable media that store executable instructions that, when executed by a computer, cause the computer to perform acts comprising: displaying an indication of a first document, said first document being in a document space; determining, by using a chooser, a choice of a second document to be read based on there being a sufficient level of dissimilarity between (a) one or more documents that comprise said first document, and (b) documents in said document space other than said one or more documents; finding a centroid that represents said one or more documents, said determining comprising comparing documents in said document space with said centroid; and after said first document has been displayed, displaying said second document as a result of said second document's having been chosen by said chooser.
1. One or more tangible computer-readable media that store executable instructions that, when executed by a computer, cause the computer to perform acts comprising: displaying an indication of a first document, said first document being in a document space; determining, by using a chooser, a choice of a second document to be read based on there being a sufficient level of dissimilarity between (a) one or more documents that comprise said first document, and (b) documents in said document space other than said one or more documents; finding a centroid that represents said one or more documents, said determining comprising comparing documents in said document space with said centroid; and after said first document has been displayed, displaying said second document as a result of said second document's having been chosen by said chooser. 9. The one or more tangible computer-readable media of claim 1 , wherein documents in said document space comprise electronic representations of paper documents.