There's a great article on it that I'm struggling to find. But essentially, the Shazam app and related apps built on their tech are used as a massive A/B testing tool now by artists. Roll out 3 versions of the same song to 3 similar cities in the Midwest and see where it gets the most shazam lookups.

If I recall correctly a few years back they were doing $100m a year by basically being able to give everyone in the music industry insight into what's the most popular and upcoming songs in every major city.

However, with the popularity of Spotify I'm guessing they're losing a lot of market share in the mass music metrics space.