Eis um estudo que me parece muito duvidoso (muito, mesmo...). Mas mesmo assim aqui vai:

«According to a national [Inglaterra] survey from independent research agency, BMRB, latest figures suggest that over 10% of the adult population have downloaded a podcast in the last 6 months and figures will continue to grow.
Among adult internet users, 17% have downloaded a “podcast” in the last 6 months (rising to 28% among 16-24 year olds) and 24% are likely to download a podcast in the next 6 months.
“The findings suggest that up to 7.9 million adults could be downloading podcasts in the next 6 months, which represents a massive opportunity for advertisers and media owners alike,” said BMRB marketing director Steve Cooke.»

fonte: «A quarter of all adult internet users will listen to a “Podcast” in the next 6 months», BMRB, 15/3/06