I can add a short bit of info about what it is not. It is not learning, for machines cannot learn. The two words that make up the term ‘machine learning’ when combined in that order result in a logical contradiction and a thing which is logically impossible. In short, if a machine could learn it would no longer be a machine. ‘Deep’ is also a pseudo modifier term that when used in the context of machine ‘learning’ or any other technomilieu means so many different things to so many different people that it is essentially meaningless. Mostly, it functions as a hype multiplier. Have a technology product or domain that gets some hype, but you want to take it to the next level, just throw a “deep” in front of it and watch the tech news media cream their jeans in front of your eyes.