FUSSP is a label sometimes applied to a mechanism whose ability to block spam and/or phishing has been overhyped. It is sometimes used with a tone of gentle amusement, as when an idea tried and found lacking several times is introduced yet again. At other times it has been used as a term of derision when applied to a technique the speaker takes issue with for some reason.
As phishing has become more common, the alternate phrase Final Ultimate Solution for Spam and Phishing has been used.