I was chatting with Victor Raymond the other night and he noted how common it used to be to name one's campaign. You didn't ask your friends, "Hey, you want to go over to Bob's place and play D&D tonight?", you said, "Hey, you want to go over to Bob's place and play in his Everwhen campaign tonight?" When I was younger, I remember the older guys used to talk this way and so it was something I consciously imitated. It made sense, too, since I'd always read about Gary Gygax's "Greyhawk campaign" and, much later, Ed Greenwood used to speak of "Forgotten Realms campaign" in the pages of Dragon. Plus, gamers were always saying stuff like, "In my Emaindor campaign, I don't allow Neutral-aligned clerics" or "In my Dark Realms campaign, I allow half-elves to take up any class."
Until Victor reminded me of this, I'd forgotten about this phenomenon, even thought I've actually talked about it before, if only obliquely. My gut instinct is that naming one's campaign is a way of clearly establishing it as its own unique thing. Sure, the referee may use the D&D rules, but those rules are subservient to the campaign itself, as imagined by the referee. So, if the referee doesn't like demihuman level limits or wants to introduce level 10 spells for magic-users, he does so and no one gives it much thought, because this is his campaign. I'm always gladdened when I see this tradition of old continued today. It's a small thing perhaps, but I like the practice of naming one's campaign and all that it implies.