This is me being a bit bitchy, TBH.
In discussing RPGs, you will frequently be called upon to back up your words. Sometimes, these are statements of fact regarding the rules.Sometimes, these are opinions based on personal taste. Either might involve specific examples, either hypothetical, exemplary, or textual.... "What if", "This one time", and "The Book says".
Hypotheticals are things that might happen... a scenario that could occur. Exemplary examples are things that did occur. And textual examples are things written in books, articles, or, depending on the subject, other mediums; if you're discussing Star Wars, textual examples will frequently include movies and episodes. And if you make a textual argument, you need to cite your source.
I'm not your high school teacher. I'm not going to insist on MLA format and a Works Cited page. But if you can't cite it, I won't bite it, and you've got to tell folks where your ideas come from. Is it by the book? Which book? Where? We may all understand what you mean when you say "the DMG", if we're all discussing the same edition, but that's a big book. Where on the hundreds of pages of information did you mean?
You might make a general statement "In the PH, the entry on dwarves says" tells me to look in the PH in the entry on dwarves; I don't have a page number, but if I can find the entry on dwarves (Table of Contents! Index!) I can find where you're talking about. If you reference a given monster in the Monster Manual, that's usually simple matter of alphabetization.
I often prefer to be more specific; I like parenthetical citations for discussion boards, since they are succinct, and we're often drawing from the same corpus. If we're discussing Dark Sun and I say (DMG p. 17), chances are I mean the 2nd or 4th edition DMGs, depending on the context. But I might say (3.5 DMG p. 17); it tells you quickly which book I'm referencing, so you can go reference it, too. So you can check my work, and the context of the statement.... maybe I'm misquoting. Maybe I've missed something. Maybe I'm lying. The citation lets you check, and makes the conversation fuller.
Cite your arguments. It makes for better arguments, better discussions, and if you won't cite it, why should I believe you?
If they won't cite it, you shouldn't bite it.
