A glaring oversight!
Cheese thread - originated as a common reply to a complaint thread -- "would you like some cheese with that whine?" That morphed into posting pictures of cheese, or just statements like "I like cheese." Moose was added later, an anachronistic reference to a line from the closing credits of Monty Python and the Holy Grail: "a moose once bit my sister."
Mind you, moose bites can be pretty nasty . . .