• by Erik Sass  @eriksass1, April 14, 2009

After a quiet launch last year, Clear Channel Radio's IHeartRadio, a national digital music-on-demand service, has rapidly increased popularity, at least among early-adopting tech addicts. In its most recent conquest, BlackBerry users have downloaded its streaming audio application over a quarter million times since it became available April 1, making it the second-most-popular application offered by BlackBerry.

It's also currently the top media application. On average, downloaders spend 73 minutes a week listening to the service.

The popularity with BlackBerry users builds on earlier successes in the mobile arena. In October, the IHeartRadio Web site was the most popular free media application on the new iPhone, and the seventh-most-popular app overall, according to Evan Harrison, the president of Clear Channel's online division, who has led the expansion of Clear Channel's digital offerings.

Currently, it's the third-most-popular music download app at the Apple App store, following Pandora and Shazam, with over 1 million downloads as of March.

Debuting last year with little fanfare, the IHeartRadio Web site allows users to get on-demand streaming audio from 150 radio stations, delivered via cellular networks or Wi-Fi. It was launched along with a raft of other digital initiatives from Clear Channel, including new content offerings, new means of distributing content, and new resources for online advertisers.

In May, the company announced a deal with Clearspring for widget syndication, which will allow users to link their Web pages to audio and video content on Clear Channel station Web sites.

On the ad sales side, Clear Channel also announced a partnership with StudioNow, an online network of video ad freelancers, to help local advertisers produce professional-grade video and display ads for Clear Channel station sites.