—Performance: In first 20 weeks, the iPhone app has been downloaded more than 1 million times for an average of 50,000 downloads a week, and usage is growing by 13 percent per week. It continues to be in the top 100 free apps list and is the No. 4 free music app.

—Online and mobile importance: The Clear Channel Radio attracts 20 million unique visitors a month online, and the iPhone mobile app attracts 146,000 unique listeners a week. Harrison said the investment is justified. “Literally in LA, there are likely 20,000 to 25,000 more listeners between online and cellphones. It’s like adding another radio station…We are growing the audience, and there are more opportunities.” He added: “For us, it’s paramount that we make it easy for our listeners to stay connected with our stations, whether it’s at their desk, in their car or while mobile. It’s a natural progression for us.”

—Revenue opportunities: Harrison said the mobile revenue opportunities are currently limited to the 15-30 second ads that are already playing on air. But soon, they’ll start selling interactive ads. As a trial, they have been offering users a chance to enter to win a $100 gift certificate to iTunes. “We wanted to test everything before be offered it to advertisers. We wanted to see what kind of offer would get what kind of results. We got a high click-through rate, and people followed through to sign up with the offer.”