Earlier in May, Focus Features, the specialty label of Comcast Corp.’s Universal film studio, released Obsession from 26-year-old YouTuber Curry Barker. The movie, which cost less than $1 million to make, has become Focus’s highest-grossing title in North America with $104.7 million in sales. More tickets are being purchased for Obsession from one weekend to the next — a rare feat achieved by only a handful of cultural sensations such as Titanic in 1997.