Yuval Kaminka was faced with a difficult choice. The Israeli entrepreneur had built a successful music learning app called JoyTunes, and he found that it was particularly beloved by professional music teachers. In the span of months, “we saw a vibrant community of teachers revolving around the apps,” he says. All the metrics were growing: retention, engagement, number of student profiles per teacher, and so on. “All these figures really blew up. We saw it was really making a difference.”
The accounts teachers were setting up for students–who use the app to gamify music learning–comprised a very significant part of JoyTunes’s revenue. Every time a teacher set up an account, either for themselves or their students, they paid either $10 a month or $60 per year. Power users wound up paying as much as $1,000 a month. Kaminka says that about 40% of his profits came from music teachers.