Method of processing an e-mail to determine a categorization thereof including a sender type and a message type, comprising: receiving an e-mail including a header having header fields and body having content; if the e-mail is not junk e-mail, determining the sender type of the e-mail from potential sender types, via first analysis of the header and the body including application of at least one first complex rule, each applied first complex rule including elementary rules specific thereto, at least some of the elementary rules specific thereto including regular expression analysis; if the e-mail is not junk e-mail, determining, a message type of the e-mail from potential message types, via second analysis of the header and the body including application of at least one second complex rule, each applied second complex rule including elementary rules specific thereto, at least some of the second elementary rules thereto including regular expression analysis.