Informal To send an unsolicited email message in an indiscriminate way (or, as a noun, the actual mail message). Formerly a low-level problem, tens of billions of spam emails are currently (2008) sent daily. The purpose of such emails varies, with advertising and fraud being common. Email addresses are gathered from websites and other Internet sources, as well as from users’ lists of contacts by malware that infects their machines. These address lists are used by software that can send out huge quantities of spam automatically; only a minute proportion need generate a financial return to make the operation profitable. Software that identifies spam and separates it from genuine email messages is now an essential part of all email clients. (The word ‘spam’ derives from a Monty Python sketch concerned with excessive offerings of cooked spam.)