There is an old, old joke:
A group of cavemen (it’s old, I said) are sitting around a fire. They’ve known each other so long, and so well, that they’ve simply assigned numbers to all the jokes. So they’ll sit around the fire, and one will say “23”, and the others laugh uproariously. “53”, says another, and they roll on the cave floor.
One night a fellow from the tribe on the other side of the hill visits, and after butts are sniffed and beer quaffed, he observes the locals in this ritual. He asks what’s going on, and Ug tells him. After a few more beers, he decides to try his hand at it. “42”, he hollers out.
Silence.
The party breaks up, and he pulls Ug aside to ask if 42 is an unfunny joke, or not assigned. Ug says “No, it’s funny. It’s just how you told it.”
In the online circles I frequent, that role has now been taken on by xkcd. In any comments section, someone will link to an xkcd cartoon, and it’s gotten to where I only have to see the number and context to know which it is.
For what it’s worth, one of my climbing buddies says the same things so often, I assigned them numbers, and for a while, we’d just say 2, or 5, or 21, and the locals knew which one you meant.