For example, this question: What does the term "carebear" mean in Eve Online?, or a hypothetical question about what "gg" means. Do they fall under this site's purview?
Jeff has stated - in the context of other sites - that "there is no such thing as a stupid question". And like they say on "Who Wants To Be A Millionaire" a question's only easy if you know the answer.
Someone who is new to a game won't know the "common" terminology, especially if it's used by everyone else with little or no context. So rather than showing yourself up as a complete noob on the game you need to ask the question somewhere else.
Here would seem a good place.
Why not? These are concrete questions that are not really subjective and are very answerable - most likely they can all have a "most correct single answer".
And it's very gaming related, obviously.
It depends on the term being discussed. Some definitions are very clear (What is frag in FPS?) but some terms might be considered subjective.
For example I strongly disagree with the second definition of carebear on UrbanDictionary (the one about Eve-Online)