13 February is a chance to celebrate this flexible medium – does part of its strong future lie in storytelling by podcast?

Like the broadcasters that have historically held the key to its distribution, radio the medium is changing. Four years ago February 13 was designated by the UN as an annual date to champion radio around the world. As shortwave transmitters are turned off, and audiences are forced to shift to FM, in other places the move is from FM to a growth in digital-only services.

Just last month in the UK, BBC Radio 6 Music, a digital and online-only station focusing on ‘alternative’ music, hit a landmark 2 million weekly listeners. Another of the public broadcaster’s digital-only stations, Radio 4 Extra, reached a new high of 1.7m listeners. R4 Extra is the BBC’s spoken-word archive station, focusing on drama and comedy. It recently aired the hit US podcast, Serial.

The 12-episode series was released weekly online, and gripped audiences following the true-crime reinvestigation of a teenager’s murder in Baltimore in 1999. Serial’s creator, journalist Sarah Koenig, interviewed the man currently serving time for the murder – who has always maintained his innocence – revisited police and court material and analysed new evidence.

Serial’s popularity suggests the global appetite for ‘audio storytelling’ has been underestimated

As well as being broadcast over digital radio, Serial’s release on Apple’s iTunes store broke listening records, being the fastest podcast on the platform ever to reach 5 million downloads. According to the Guardian UK, not only was the series a hit in the US, Canada, UK and Australia, but it topped download charts in Germany, South Africa and India. Podcasts have been around for years, but the high level of smartphone ownership around the world and a push for quality in content-creation have now made them come into their own.

The programme’s popularity suggests the global appetite for ‘audio storytelling’ has been underestimated. And it has demonstrated radio’s versatility as a platform for long-form, investigative journalism, and indeed, that documentary can be a hit with listeners, not just viewers. Serial’s success has also shown that perhaps radio can hold its own in this digitally enabled age of consuming content back-to-back. Could binge-listening to podcasts challenge TV?