I think it is polite if using a newish or strange acronym to explain what it is in full when first used in a post. I imagine that even the newest Newbie can work out DF'd etc from the context of the post.
Where a new one from within the Borg ( < everyone understand Borg?) comes into existence I echo what Happy Dad says above, please give us it in full, and correctly, at least once, as I don't like to be corrected by my family or other JW's when I use their esoteric terms.
LDC is defined incorrectly in a post above. This is not helpful, JW's love to find fault with our words so that they can ignore our whole argument.