Despite claims this phrase
originated on "The Simpsons", it actually existed
long before it was used in the show. The phrase
is intended to portray the distortion of facts when passed from person to person.
Its use in "The Simpsons" was accurate; Bart
starts a rumour by whispering to one person who whispers it to another, etc. By the time the rumour reaches the front of the crowd, the phrase
"Purple monkey dishwasher" has been added to the end due to people mishearing the original rumour as it passed from person to person.
Due to the popularity
of "The Simpsons", the phrase
has since become a commonly
to opinions stated based
on hearsay and unconfirmed rumours.