By Chris Vallance
BBC News, Ontario, California
Hundreds of podcasters from 22 countries recently gathered at the Portable Media Expo and Podcasting Conference in Ontario, California, for the first major podcasting convention to be held in the US.
Podcasts are changing the content of radio
It is a mark of how mainstream podcasting is becoming world-wide that one of the attendees from the UK, Ewan Spence, is nominated for a Scottish Bafta for his series of podcasts from the Edinburgh festival.
But does podcasting spell the death of radio?
The answer that seems to be emerging from this conference is that it depends on the type of radio in question.
Adam Curry, widely credited as the "podfather" for his part in the development of podcasting, has attracted millions of dollars in venture capital funding for his Podshow and Podsafe Music Network businesses.
But he is convinced there remains space for traditional radio, particularly in the sphere of news.
"If we find Osama Bin Laden, don't go running to the iPod - you'll be severely disappointed," Mr Curry told the BBC.
News radio is somewhat insulated from the effect of podcasting by the need to cover major events live. But many feel podcasting is challenging complacent broadcasters, who have allowed quality and audiences to decline.
Leo Laporte, a talk radio host in Los Angeles and the creator of the hit podcast This Week in Tech, thinks podcasters are changing radio for the better.
"Radio has been moribund for a couple decades, podcasting is reviving this art of radio - it's a complete renaissance."
One aspect of this renaissance is "narrowcasting" or "microcasting" - broadcasts targeted at niche audiences.
It is radio that focuses on particular interest groups. Examples include "The Mommycast: a podcast for mommies everywhere", or "The Good Beer Show", which offers reviews of micro-brewed beer hosted from a tavern in Indiana.
"We're talking about a million different niches," said JD Lassica, a pioneer in the field of citizen-produced media.
Many at the conference predict the greatest effect of podcasting on traditional radio will be in music broadcasting.
Given copyright restrictions, podcast music shows are limited to so-called "podsafe music", where the musicians publish under licences that allow internet downloading.
Most bands that produce "podsafe music" are unsigned bands, independent of the major record labels.
Mr Curry, a former MTV presenter, believes that is bad news for the major record labels.
"The end result will be that podcast music is going to route around the entire [music] industry," he said.
"The music business itself is heading for a meltdown because all the tools are available for any artist to sell directly to the consumer."
But there are signs that traditional broadcasters are waking up to podsafe music.
At the recent Pod Con UK conference held in London, Virgin Radio announced that it would be including podsafe music in some of its podcasts.
As podcasting changes the content of radio, the way we listen to radio is changing too.
Tech-geeks like to speak of "convergence", of the coming together of the different ways to listen to radio as broadband and wireless technology become more prevalent.
There are already mobile phones that enable you to download podcasts - in effect, turning your phone into a radio tuner - that has the money-men interested.
"We think there's a huge a market, that will allow podcasting to be extended to the 2bn wireless phones across the world today," Adrian Smith of Venture Capital firm Ignition Partners said.
"In a pretty short number of years ring-tones have become a huge multi-billion dollar market and that suggests podcasting could be a very large market indeed."
Despite the emphasis on new technologies and ways of making money from podcasts, there is broad agreement that the key to success in podcasting and in traditional radio is the same.
As Mr Curry says, however clever the technology, "you need this wonderful piece in the middle which is the guy talking about something he's passionate about".