Bib:
Here's my standard -- as a writer I know the audience to whom I am writing. If I don't know that I am not a good writer. And if, as an astute "reader" of my audience, I truly believe that the majority (or even a significant minority of them) will know what yaud (though of course as a purist I prefer the more traditional yawd) means, then I will use it, but if and only if there is a need for it.
I would not for the life of me use it in say a column about horse-racing; in fact, I cannot see a use for it at all. It is obscure and/or antiquated, and it's a fun word to bandy about in a discussion like this, but it has no real place in literature because too few people know what it is. If your audience has to go scurrying to the OED twice on every page you have FAILED as a writer. It is the writer's duty to communicate, not to obfuscate, or even to educate about odd words (unless that's the stated purpose of the written piece, of course.)
I'd use broken-down nag or hack, but not yaud.
People who routinely use words like this just to see the look of incomprehension on the faces in the audience or to be able to smirk inwardly or outwardly when asked what the word is, are pretention boobs, in the main, and are to some extent beneath contempt. I hope Bill Buckley is reading this. Bragging is unbecoming.
