iHeartRadio, the online arm of the traditional radio giant formerly known as Clear Channel, said Friday it hit 70 million people who have registered to listen to digital stations.
The growth reflects both the growing popularity of streaming music generally as well as iHeartRadio's promotional advantage of being attached to the country's biggest terrestrial radio company, iHeartMedia, that also operates a high profile concert series of the same name.
The milestone also comes ahead of Apple expected toMonday at its annual Worldwide Developers Conference.
Many of iHeart's listeners come to stream live feeds of the company's traditional radio stations, which doesn't require registration. Listeners register with the site when they want to create or listen to a custom station based on, for example, a particular artist or mood, or when they want to hear an on-demand podcast.
It's difficult to gauge iHeart's size versus competitors based on registered users because most of its rivals -- such as Pandora and Spotify -- report monthly active users. Registered users are a running total of the people who have signed up for a service at any point, while monthly active users are those who tune in at least once in a given month.