24. The method of claim 1 , wherein the step of using a computer to parse the text of each of the first and second documents into constituent units further comprises using the computer to parse the text of each of the first and second documents into sentences.
1. A computer-implemented method for comparing content overlap between a first electronic document and a second electronic document, comprising: receiving, at a computer, a search request from a user for documents containing one or more keywords; using the computer to access an electronic database and present to the user a first list of one or more documents in the electronic database based on the one or more keywords, the first list of one or more documents including a first hyperlink for the first electronic document; receiving at the computer a request for the first electronic document via the first hyperlink; determining, in response to the request for the first electronic document, a second list of documents in the electronic database that are similar to the first electronic document, the second list of documents including the second electronic document, and the determining comprising: using the computer to parse a text of each of the first and second documents into constituent units; using the computer to compute a digest of each of the first and second documents based on the constituent units; using the computer to compare the computed digests; using the computer to compute a proportion of common contents between the first and second documents and a proportion of distinct contents between the first and second documents based on the comparison; using the computer to determine a date associated with the first document and a date associated with the second document; and using the computer to determine a direction of borrowing based on the determined dates; and using the computer to display to the user the contents of the first electronic document and a hyperlink to the second electronic document and a graphic indicating the direction of borrowing between the first document and the second document, wherein the graphic includes an arrow oriented to point in the borrowing direction showing a computed direction of flow of the information from a donor document to a borrower document, and wherein the graphic comprises a measure of relationship overlap between the first document and at least one of the second document and a selected portion of the second document.