Podcasting and on-demand audio are attracting new audiences, giving rise to new voices and creating new revenue sources, with public broadcasters playing a central role, according to a study by the John S. and James L. Knight Foundation released today.

Yet the fast-growing podcast ecosystem is not nearly as diverse as it could be, and public radio stations are not unified in their approach, said the report, titled “From Airwaves to Earbuds: Lessons From Knight Investments in Digital Audio and Podcasting,” prepared by Lutman & Associates and Dotman Connector Studio.

Because the report examined Knight Foundation investments in both public media and for-profit companies – through philanthropic grants and the Knight Enterprise Fund, a venture capital initiative – it provides a broad view of podcasting and on-demand audio at a time of rapid growth. Knight is interested in podcasting’s potential to inform and engage communities, both as journalism and as an alternate form of storytelling.