11. A method comprising employing a computer system to: generate an electronic communication feature count indicator comprising a plurality of feature counts for the electronic communication; generate a text line structure indicator characterizing a line structure of the electronic communication, the text line structure indicator comprising a data structure selected from a group consisting of an ordered list and a tree of text line type indicators, a position of each text line type indicator in the data structure being indicative of a position of a corresponding text line type in the electronic communication; determine a composite hyperspace distance between a vector representing the electronic communication and a predetermined vector, the hyperspace distance being a function of a Euclidean-space distance dependent on the feature count indicator, and of an edit distance dependent the text line structure indicator; and classify the electronic communication according to the composite hyperspace distance.
11. A method comprising employing a computer system to: generate an electronic communication feature count indicator comprising a plurality of feature counts for the electronic communication; generate a text line structure indicator characterizing a line structure of the electronic communication, the text line structure indicator comprising a data structure selected from a group consisting of an ordered list and a tree of text line type indicators, a position of each text line type indicator in the data structure being indicative of a position of a corresponding text line type in the electronic communication; determine a composite hyperspace distance between a vector representing the electronic communication and a predetermined vector, the hyperspace distance being a function of a Euclidean-space distance dependent on the feature count indicator, and of an edit distance dependent the text line structure indicator; and classify the electronic communication according to the composite hyperspace distance. 13. The method of claim 11 , wherein the composite hyperspace distance is equal to a sum of the Euclidean-space distance and the edit distance.