Clear Channel's online radio service iHeartRadio hit 50 million registered users faster than music rival Pandora, Facebook and Twitter.
The service launched only three years ago, according to Business Insider. The company reported last month that it had close to 100 million unique visitors.
Clear Channel is the biggest owner of terrestrial radio stations in the U.S., and has about 245 million people listening to its 850 AM and FM radio stations each month.
Streaming music services have grown in popularity in the past few years, with revenue gained with these services increasing to over $1 billion around the world last year, CNET reported.
Clear Channel faces many competitors in the market, including its main rival Pandora, the Web's largest radio provider, which hosts 77 million active listeners each month. Other competitors include Spotify, Beats, Google, Apple and Amazon.
Bob Pittman, chief executive of Clear Channel, said that having 850 radio stations in the U.S. does not guarantee iHeart's success, CNET reported.
"If you look at the history of traditional media companies, the heft alone isn't enough," he said in an interview.
Pittman also said he doesn't combine radio and other options when looking at iHeart's competition.
"Let's not combine music collections and radio as one category," he said. "They rarely live together. Now it appears that downloads replace CDs, maybe subscription replace downloads, but it's still the same thing. It's still your music collection.
"When you go to the radio, you want to hear what's going on in the world."
Chief financial officer Richard Bressler said during a conference call in April that iHeart had 47 million listeners at the end of March. He also said mobile usage made up 66 percent of all user listening hours, Billboard reported.
Clear Channel also brought up iHeart being added to new devices, such as the Samsung Gear 2 smart watch and the Amazon Fire TV set-top box.
The company has also been aiming to use a primetime awards show and an annual music festival to expand the iHeart brand, CNET reported.
"The future is some sort of electronic - today it's digital, it's streaming," Pittman said. "We're doing open heart surgery on a beating heart ... we're all trying to build this digital market in an intelligent way."
