Anything that goes from Zero to 1 (Peter Thiel). An example, pre-airplane civilization to a jet set civilization. I'd say that in 2016, that was the year for ML to seriously influence world events. In 2019 I'd give a serious look at this list https://www.ycombinator.com/rfs and chances are the next big thing isn't on it. Personally, I'm shorting credit card companies since 50% of millennials have maxed out credit cards.