When I get a notification via Google Plus app, driving me to their app because there's something that I've expressed interest in, is that "advertising, promotion, or direct marketing"? Or from a Facebook app? Or any game informing me it's my turn?

Yes, they drive app use, and perhaps even later revenues, but in a way that's in harmony with my intent when installing the app and expectations. It's like "you've got mail (that you requested)". You can squint and call it marketing, but then almost every notification that increases use of a profitable app is also marketing.