I agree. Particularly CdGing. It smells of someone trying to avoid misspelling a phrase by hiding it with an uncommon acronym.
Come on guys...this isn't texting or twitter. There isn't a character or word limit. It doesn't take that long to type out what you actually mean, so that a wider array of your audience actually understands what you are trying to communicate.
WDYHAA? (What do you have against acronyms?)
Seriously, though, while I've never seen CdG or NADS before*, I was able to figure them both out pretty quickly (even though NADS should really be NADs). And frankly, acronyms do help alot if it's a term you're going to use frequently. Probably not necessary in this case, but imagine a discussion in the rules forum where you're discussing the merits of AC-based attacks and attacks against other defenses. "Non-AC defense" repeated over and over would get quite, err, repetitive, if you'll excuse the redundancy. Not to mention "NAD" is a lot more succinct and less clunky than "Non-AC defense."
Acronyms have always been a major part of every community. Whenever you've got people with specific knowledge about a common field, I guarantee there will be clunky, but frequently used, terms which will be reduced to an acronym, because they're easier to think about, easier to write, and easier to read if you're already familiar with them, as the expectation would be.
Also keep in mind that this isn't something limited to acronyms. I guarantee you there's at least one person reading this thread right now who doesn't know what a gish is, and unless someone explains it to them or they look it up they'll never figure it out because there's no context here to figure it out from.
Acronyms are just another form of slang, and even if you don't know them you should be able to figure them out from the context if you're familiar with the concepts already.
*Just wanted to say "Ha ha Asmor says he's never seen nads before!" to steal the thunder from whichever joker was going to try and do that first.