http://www.conversedigital.com/digital-strategy/podcasting-statistics-trends-future

This web page I came across talks about podcasting statistics and the future of podcasts. 

It's quite informative and insightfull about the world of podcasts as it has charts about how popular podcasts have become. This came in useful when looking at how people listen to the radio and what age groups of people listen to the radio. Even though it is a fair short article I have managed to pull a fair bit of information out out it.