A non-spam e-mail message; a legitimate e-mail message that is blocked or filtered because it contains one or more keywords normally associated with spam messages.
A common concern among IT managers is avoiding spam countermeasures that create "false positives" deletions of real messages that contain an element commonly found in spam.... There is even a recently coined term for this: ham.
Brendan Weston, "Costly 'spam' flood soaks all office ranks," Financial Post, February 17, 2003
Jason Rennie of MIT's Artificial Intelligence Lab is writing code he says eventually will help filter spam text that is manipulated to be unrecognizable. For example, his program could recognize mort!!!!gage used in the place of mortgage, a common spam word.
But there are problems with filters, Rennie said, because one person's spam is another person's "ham," hacker-speak for desirable e-mail.
"If you work for the company that makes Viagra, you probably don't want to be filtering any e-mail with the word Viagra in it," he said.
Theo Emery, "MIT Conference takes aim at spam," The Associated Press, January 17, 2003
I'm not telling you anything you don't already know when I say that spam junk e-mail or unsolicited commercial e-mail is a virtual plague upon the earth. Billions (yes, billions) of spam messages are sent daily, and it's a rare e-mail user who doesn't get at least a few get-rich-click come-ons and "Enlarge your [insert body part here]" offers each day. Those of us whose Inboxes are polluted throughout the day with dozens of samples of this online pestilence are fighting back by employing filters that automatically trash incoming missives with subject lines containing words and phrases such as "you're a winner" and "free money." Unfortunately, these filters sometimes corral legitimate messages, or false positives. (I once almost missed an important message from my bank because my filter included the phrase, "credit card.") Since Spam (the meat substance) is a kind of "fake" form of ham, and since these legitimate messages are "real" compared to spam messages, Netizens have taken to calling them ham, a usage that has now been around for about six months.