People who try to promote their services through mass email shots of unsolicited "junk mail", or other under-hand practices such as cloaking.

Electronic junk mail. Spam is generally e-mail advertising for some product sent to a mailing list.

The perpetrators of email spam, who send nearly identical messages to thousands (or millions) of recipients. Spammers often harvest addresses of prospective recipients from Usenet postings or from web pages, obtain them from databases, or simply guess them by using common names and domains. By definition, spam occurs without the permission of the recipients.