There is a lot of questionable information doing the rounds on social media. Many contributions are distorted or exaggerated, and some are just plain wrong, rest assured we have made every effort to verify what follows.
There is an old Australian term which can be aptly applied to a false rumour or theory: it’s a ‘furphy’. The use of the word ‘furphy’ for misinformation can be traced to Australian soldiers in the First World War. A contributor to The Herald (Melbourne, 22 August 1929) explained the ‘Etymology of Furphy’ this way,
Sir – Regarding the origin of the word ‘furphy’, meaning a rumour, they were in use in Australian camps in war-time bearing the maker’s name in large black letters.
The drivers of these carts were generally great purveyors of rumours. Driving around to different units those tales spread very quickly and generally were without foundation.
Humourist writer CJ Dennis may have been the first to use the word in print in 1916, in The Moods of Ginger Mick. Mick, now in the Australian Army, muses…
I know wot i wus born fer now, an’ soljerin’s me game,
That’s no furphy; but I never guessed it once.
The term furphy, which may have originated in the large Broadmeadows army camp in Victoria early in the First World War, became generally accepted on every front where Australian soldiers served.
Cobb+Co Museum is fortunate to have a Furphy watercart in the collection. The watercarts were used throughout Australia. Besides keeping soldiers hydrated they were used to cart water for livestock on farms, and by road building gangs for dampening down dust. The watercarts were made in the foundry of J Furphy & Sons, Shepparton Victoria. The company began producing agricultural equipment in 1873 and is still in operation. Proprietor John Furphy, a devout Methodist, had moralist messages cast into the ends of the Furphy tanks;
Good, better, best
Never let it rest,
Till your good is better
And your better best.
John Furphy also had a message in Pitman shorthand on his tanks ‘Water is the gift of God, but beer is a concoction of the devil. Don’t drink beer.’ Furphy may have had a point. He evidently had a sturdy disposition, surviving a level crossing accident with a train in 1898. His two horses were killed, the buggy smashed, and John hurled through the air and knocked unconscious.  But he recovered and lived another 22 years until 1920, long enough to hear his name enter the Australian vernacular. 
Sadly, the word furphy is not heard so often today, but does comes up in Parliamentary debates when politicians accuse those of the other side of the House of ‘spreading furphies’, which is a little safer than calling their political opponents outright liars.
A related modern expression used overseas is ‘water cooler gossip’  but it has not gained wide acceptance in Australia. Perhaps in these days of questionable information on the internet, the term furphy should make a comeback. Unlike ‘fake news’ the word furphy suggests that the rumour or information may be exaggerated or distorted, but also, possibly, have an element of truth. It is a word for sceptics rather than cynics.
Read more about the Furphy water cart in Cobb+Co Museum’s collection.
 CJ Dennis 1916, The Moods of Ginger Mick. Angus & Robertson, Sydney.
 ‘Sensational Railway Accident’ Albury Standard & Wodonga Express, 4 Nov 1898. P29.
 Benalla Standard, 1 Oct 1920. P3.
 Longman Dictionary of Contemporary English Online, Pearson Education, London.