1. An interactive search results presentation system, comprising: a general purpose computing device comprising a display and a user interface selection device; and a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to graphically display the results of a search to a user on said display via an interactive search results window in which the user views and filters search results items on the display, said search results window comprising, a graphic data presentation sector which displays a histogram of the search results items in terms of a user-specified independent variable corresponding to a common attribute of at least some of the search results, wherein the bars of the histogram each represent a histogram bin corresponding to a particular range of the independent variable and each have a length proportional to the number of search results items determined to be in the associated bin; and a selection pane covering a fractional region of the displayed histogram along the axis of the independent variable, said selection pane being visually distinguished from the remaining parts of the histogram and representing a currently highlighted portion of the histogram; and wherein upon user-selection of the portion of the histogram highlighted by the selection pane encompassing two or more of the bars of the histogram, a new histogram is computed for just those search results items associated with the selected portion of the histogram and displayed in the graphic data presentation sector in lieu of the previously displayed higher-order histogram, thereby effecting a user specified filtering of the search results.