I heard an interesting thing this morning. Someone on a panel discussion mentioned that he doesn't think in 5 years time we'll be talking about different kinds of marketing as what they are today. So, for example, he said "Why call it mobile marketing? Why call it interactive marketing? Why call it direct marketing? It's just MARKETING." No, brother, it's not just marketing.
The medium defines the players, not the other way around. Here's how I finally came to resolve it for myself. A road cyclist is not the same as a mountain biker. A painter will tell you she/he's a painter, not just an artist. And a painter and welder are not the same thing, although the end result is art. Would you put Baryshnikov next to some titty bar dancer and say, "See? Same thing!"?
No, you wouldn't.
If someone is in the mobile marketing world, they're in the mobile marketing world. Sure, they're a suburb of marketing but they don't want to have to pay the same taxes or put up with the same legislation as the city.
Condense the channels of marketing and we're all just one homogenous industry. The differences make the difference, man.