Um, ok, well some things are references to old fights on MN, eg sausage rolls, formula feeding, slogans on t-shirts (apparently) weaning spoons v BLW, Mac Donalds, 4x4s, chav (Burberry) the cat and the football, ear piercing (oh we haven't argued about that for ages!).
Some things refer to well-known posters' names eg cod, rhubarb, Mars, Twiglett, MartianBishop, Sherlock (aka LGJ, aka BreeVanDerCamp).
Some things are approved of by certain Mumsnetters eg Waitrose, Boden, Mooncups, Soupy the bat, fair trade (apparently!)
Some things caused funny moments (or rows) on Mumsnet eg the red rug was a thread started by an impoverished Mumsnetter who nevertheless had money to buy a new rug. The tablecloth is a reference to a funny thread about tablecloths. The pheasants were mentioned by Lavenderr (hence picture of lavender) who thought we would all approve of her son poaching.
The organ doner thing refers to Misdee's dh who is waiting for a transplant (he is pictured too).
Judge Flounce was a famous troll on MN.
Umm, anything I have missed?