In programs used to filter spam, a false positive is a legitimate message mistakenly marked as spam. Messages that are determined to be spam may be rejected by a server or client-side spam filter program and returned to the sender as bounce e-mail .

One problem with many filtering tools is that if they are configured stringently enough to be effective, there's a fairly high chance of getting false positives. The risk of accidentally blocking an important message has been enough to deter many companies from implementing any anti-spam measures at all.

28 Jan 2006