Someone above mentioned a Jokewriters' Convention where they clled out numbers, because the jokes were so well known to them all.
A friend of mine went to one and shouted out "742" and everyone laughed.
When he asked why they were laughing so much, someone said "We've not heard that one before"!
Quack. p.s. I like the mudcat because of its eclectic mix of knowledge and interests. There is so much to dip into. I suspect that regular visitors will gravitate towards threads which suit their personality, and therefore make their Mudcat Friends within a particular school (fish joke -Number 643 I think?) of thought.
This means that it can hold many diferent shades of opinion without too much aggravation and falling out - Plus it embodies an old principle that you can call your friends names but you must be polite to strangers!