WHEN Jamie Morton discovered that his 60-year-old father had written an erotic novel called “Belinda Blinked”, he was appalled. A few weeks later, when reading passages of the book aloud to two university friends over dinner, Mr Morton saw the funny side—and a creative opportunity. “It was so bad,” Mr Morton says, “it was gold.” The three decided to record their reactions to Belinda’s not-particularly-erotic escapades and the author’s idiosyncratic syntax. “My Dad Wrote A Porno”, a 13-part podcast and surprise hit, was born. The choice of medium was significant. Podcasts, series of digital audio files that users can download or stream from MP3 players and computers, were first created in 2001. This was also the year that Apple launched the iPod, the device from which podcasting takes its name. Although it is now, in tech terms, a doughty 15 years old, it has developed only fitfully. While some veteran shows, including “This American Life”, “RadioLab” and “How Stuff Works”, have been broadcast regularly since their launches in the middle of the decade, many more withered away to nothing as quickly as they had sprung up.

The first generation were bedevilled by a lack of professionalisation and an increasingly crowded market. At the same time, podcasts were facing fierce competition for audiences’ attention from a plethora of other new digital-native products including Facebook, YouTube and Twitter. Podcasting, allied as it was with radio, had an old-fashioned air from the beginning. Another difficulty was that, like other media, many podcasts were reliant on advertising. Reliable advertisers were scarce in the wake of the financial crash and were suspicious of newer, untried brand names. Compared with websites and YouTube channels, podcasts were disadvantaged as they are usually unable to say exactly how many people are actually listening to each episode—and therefore to each advert—because episodes are automatically downloaded to users’ devices once they have subscribed.

Over the past couple of years, though, the medium has been experiencing a renaissance. In the autumn of 2014, “Serial” (a sister podcast to “This American Life”) broke an iTunes record as the fastest podcast to reach 5m downloads. Data from Pew Research Centre indicate this is part of a wider trend. The percentage of American adults polled who had listened to a podcast in the previous month doubled between 2008 and 2015, with over a third of the population having now listened to at least one.

Other media organisations are taking note. In December 2015 Quartz, the digital-native publication from the Atlantic, published the inaugural Casties or podcast awards. The Financial Times, which has been producing podcasts for a decade and now has a dozen different series, announced that it had a bumper year of 45m downloads in 2015. And in January this year, the New York Times added another series to its smaller stable. Called “Modern Love” after the popular column, it consists of essays about relationships read by actors.

One of the reasons for this new traction is technological. Smartphones, which have better internet access, and the increasing availability of free Wi-Fi mean that podcasts are far more seamless to download or stream than they used to be. They are also becoming more popular with advertisers. Podcasts are largely listened to by commuters in cars—a captive audience, and a demographic advertisers are keen to reach. To add to the attraction, the hosts of many podcasts read out the advertising copy themselves, making ads less obtrusive and more persuasive than those on many traditional stations that are more clearly delineated by distinct voices and jingles.

The informality of podcasts, which are listened to either in the privacy of a car or that of a pair of earphones, makes them popular with those trying to advertise products that are traditionally difficult to market. Mack Weldon, a men’s underwear company, specified that its advertising copy should be “done by the podcasters in their tone. So if they swear when describing our product, let them swear up a storm.” Hosts duly obeyed. MeUndies, another underwear company, also favours podcast ads.

The privacy of the format was what attracted Mr Morton and his two co-hosts. They had previously made a YouTube series together, but felt the content of “My Dad Wrote a Porno” leant itself to audio. “We really wanted to get across this intimacy of just being friends sat around a kitchen table,” Mr Morton says. “And because the humour is based on pornography, it’s better that it’s just in your earphones, isn’t it?”

Season Two of "My Dad Wrote a Porno" is due for release later this year.