1. A method of ranking entries in a table of contents, the method comprising: transmitting a first document to a client device, the first subdocument including a text and a link; receiving from the client device a request for a second document associated with the link; dividing the second document into subdocuments, each of the subdocuments including text; assigning a label to each of a plurality of the subdocuments; comparing the text of the first document with the text of each of the subdocuments to generate a document-document value for each of the plurality of subdocuments according to the degree of association between the first document and the corresponding one of the subdocuments; ranking in ranked order the plurality of subdocuments based, at least in part, on the document-document values.