Netflix, a company that once dismissed the concept of allowing commercials around its popular streaming content, now can’t seem to get enough of them. The streaming giant said Tuesday that its ad-supported tier now reaches 70 million users around the globe, compared with the 40 million it revealed in May and the 22 million it cited in January — a growth trajectory that big marketers want to see before they take Netflix’s advertising options more seriously. Netflix continues “to see steady progre...