A Marmite is a heavy iron pot used to boil (simmer) a soup over a slow wood fire for a very long time. If you let it go long enough, you end up with a very thick sludge which lasts for ages, and is supposedly good for you...
Strictly speaking Vegemite is the Aussie answer to Marmite. It was allegedly going to be called "Pawill", but they decided to go with the name Vegemite.
My actual preference for taste is Promite....
The new Aussie OWNED spread is called MightyMite... :-) and the TV ad soundtrack is by a famous Aussie singer...
You can always use Bonox as a spread, but it's a bit runny.