In my first post, I referred to the concept of "running games" as GMing, but referred to what I do as specifically DMing. I consider myself to be a GM, but more specifically, a DM.
So, here's where I explain what I mean by that. Why I call myself a DM, even when I'm not specifically running Dungeons & Dragons.
1) It's a gesture toward the founding (and continuing) importance D&D has for tabletop RPGs. D&D started it all, and the fact that I consider myself a DM is a mark of respect for this, and a statement that I intend to carry on D&D's tradition.
2) In a certain sense, the games that I run ARE dungeons. See, the word "dungeon" is now used to refer to a prison, but that's obviously more specific than its use in tabletop gaming. "Donjon" referred to a keep or fortified place, but again, that doesn't quite line up with the way we use "dungeon," either. It's common in tabletop gaming to think of a dungeon as a subterranean location with several rooms, at least some of which are infested with monsters to defeat and which contain treasure to collect. And this comes close. But, I find the most helpful way to think of what a dungeon IS is provided by The Angry GM here.
So, when I say I'm a DM, it means my job is to present a party of players with a set of meaningful choices, fraught with both challenges to overcome and rewards to achieve.
(Plus, Dungeon Master just SOUNDS cooler than Game Master, haha.)