• by Erik Sass  @eriksass1, April 9, 2015

Jay Z’s relaunch of Tidal was yet another reminder that the audience for digital radio is growing by leaps and bounds, along with a whole range of monetization strategies and new options for marketers.

To help advertisers and media buyers keep pace with this fast-growing new medium, the Interactive Advertising Bureau is publishing a new Digital Audio Buyer’s Guide, available at the IAB Web site here.

In addition to giving an overview of definitions, delivery methods and ad formats, the guide highlights a number of favorable trends in digital audio listening. That begins with the recent estimate by Edison Research and Triton Digital that 115 million Americans, or over a third of the population, listen to online radio and streamed audio content every week. That figure is up 22% from the same time last year.

eMarketer estimated that 170 million people -- or over half the U.S. population -- listen at least once a month, with this figure set to increase to 192 million by 2019. Furthermore, digital audio offers advertisers access to the coveted millennial demographic, with 72% of consumers ages 18-34 listening at least once a month.

There’s some evidence that the big increase in digital audio listening is coming at the expense of other forms of music media: 44% of consumers surveyed by Edison indicated they were listening to digital audio instead of broadcast radio, and another 30% said it replaced personal music collections. On the other hand, 26% said digital audio was new listening time, in addition to other media.

Like most other digital media, digital audio is being transformed by the rise of mobile: in January 2014 comScore found it was the most popular mobile content category alongside games, with 79% of digital audio listening taking place on mobile devices, compared to 61% for social media activity.

The IAB guide notes that digital audio is actually the least cluttered mobile ad channel, offering precise targeting capabilities and ads that are less likely to be ignored -- and the advent of in-car mobile listening is only deepening the listener relationship. The proportion of consumers who said they listen to online radio in the car increased from 12% in 2013 to 21% this year.

Nielsen estimated that 79% of audio consumption takes place during activities that preclude visual media like driving, doing chores, or exercising.