19. The system of claim 18 , wherein the at least one processor is further caused to: receive a plurality of known spam electronic documents; and determine a plurality of unique attributes from the plurality of known spam electronic documents.
19. The system of claim 18 , wherein the at least one processor is further caused to: receive a plurality of known spam electronic documents; and determine a plurality of unique attributes from the plurality of known spam electronic documents. 20. The system of claim 19 , wherein the first attribute set and the second attribute set each comprise at least a portion of the plurality of unique attributes determined from the plurality of known spam electronic documents.