I have no idea about everyone else, but I rarely ever see MAC advertised. Direct advertising, anyway. It's sometimes featured in music videos or magazines, but I've never seen a MAC commercial (I've heard they do have a couple) or an ad in a magazine, etc. It makes me wonder how the hell their following got so large--probably all of their LE collections that keep loyalists coming back for more!
They don't rely on advertising/promotion much by any means (minus collection promo photos). And yet we know what their products are about, we know their standards of quality, etc. And you're right, we DO crave their advertising... which is really weird because a lot of us hate advertising.
What drew me in was pure and simple: quality. And they abide by my two cosmetic company rules: animal & environmentally-friendly. LE collections definitely keep me interested and coming back (i.e. quantity/variety), but I do wish there weren't so many! I think they go overboard with the number of LE collections they release.