For many, faster home internet connections meant that podcasts have already been surpassed by video. Ever since podcasts became mainstream, there were some that saw it as a bridge to video podcasts and once video podcasts became more mainstream then the former would fade away into obscurity much like the 8 track tapes and Laser Disc formats before it.

However, new research by eMarketer shows that this is not the case and in fact, podcast audiences are growing fast. In the 2007, the internet research company estimated that the total US audience stood at 18.5 million and will grow by 251 per cent by 2012 with 65 million people downloading podcasts. Of the 18.5 million podcast listeners in 2007, around 35 per cent are active listeners - as 6.5 million people will download an average of one or more podcasts a week.

Surprisingly, the report underlined how the majority of podcast were consumed via PC as opposed to portable devices, contradicting the notion that cheaper MP3 technology has been the sole reason for the rise in the medium’s popularity.

Paul Verna, eMarketer Senior Analyst and author of the new report, Podcast Audience: Seeking Riches in Niches says that the rise in the number of those listening to podcasts will lead to an increase in advertising. "As the US podcasting industry matures it is unquestionably creating a listening audience. And along with a larger audience comes increases in advertising spending tied to podcasts."

According to the research, $165 million was spent in 2007 by marketers on either sponsorship or advertising. This figure will rise to $435 million by 2012.

Steve Cody, CEO of PR agency Peppercom, who has his own podcast, RepChatter, with partner Ted Birkhahn, is unsurprised by the success of the medium and expects the number of users to continue growing.

"Podcasts remain a smart digital solution because they’re low cost, low maintenance and user friendly. We believe that as long as they remain relevant and provide value to listeners, a podcast can play a meaningful role and will continue to have a positive impact on listeners. Video is the next evolutionary step for the Web, and smart companies will determine how to incorporate video into their digital marketing mix, but the ease of producing and downloading podcasts will be a significant contributor to their success for some time to come," he said.

The report also highlighted how the following key factors will contribute to the increasing number of podcast listeners:

• - Greater ease of consumption for podcast content
• - Growing awareness of podcasting
• - Terrestrial radio’s use and promotion of podcasting
• - Increased penetration of portable players
• - The evolution of smart phones and proliferation of affordable mobile data plans