1. A method comprising: performing, by a computer system, an automated keyword analysis of an electronic document to identify a set of keywords associated with the electronic document; displaying, by the computer system, the set of keywords; accepting, by the computer system, user input indicating user-specified concepts of interest, wherein the user input includes at least one keyword identified by the automated keyword analysis and at least one keyword not identified by the automated keyword analysis; analyzing, by the computer system, the electronic document to identify locations of discussion of the user-specified concepts of interest; and displaying, by the computer system, a graph representing the electronic document and illustrating persistence values associated with the user-specified concepts of interest at locations in the electronic document, wherein, for a given location in the electronic document, the graph illustrates a persistence value indicating a frequency of discussion of a user-specified concept of interest at that location relative to other locations in the electronic document.