In typical Wired reader style, this concept of an idea that can be communicated is called a meme (and memes are often written about in digerati circles).
Classic memes that non-geeks would have heard of include the Frankie Says series of t-shirts and No, but Yeah, but No dialogue from Little Britain.
Why four?
Three or six are the perfect numbers according to a discussion between Lee van Cleef and Clint Eastwood in The Good, The Bad and The Ugly. Wikipedia couldn't shed any light on it either.
Four jobs I've had
PR operative - at present 
Foreman - heading up a shift team on the bitumen plant in the UK's second smallest oil refinery 
DJ - up north, before the young people started getting back into guitars, freebase cocaine and heroin
On the line - in a meat packing plant
Four movies I can watch over and over
The Dollars Trilogy (particularly For a Few Dollars More)
Four TV shows I love to watch
Four places I've visited on holiday
- Dublin
 - Leiden
 - Ibiza
 - Paris
 
Four favourite dishes
- As my mate Griff would say 'a big bowl of fuck-off' (a ramen noodle dish from Wagamamas)
 - A decent Irish fried breakfrast with proper black and white pudding and a side serving of soda bread
 - Rhubarb crumble
 - A well done tuna steak
 
Four places I've lived
- Liverpool
 - Galway
 - London
 - Huddersfield
 
Four sites I visit daily
It would actually be a hell of a lot more than this but: Slate.com, Wired.com, RTE.ie and ThinkSecret.com
Four places I'd rather be
Liverpool, with my mates, record shopping, sat in front of a range enjoying a turf fire
Four people I'm tagging
