I've written before about how podcasts are increasingly being targeted by advertisers as delivery mechanisms for their messages. The fact that iTunes now supports and lets people subscribe to podcasts (and the numbers for subscriptions have reportedly gone through the roof) only cements that this medium is here for a while. In fact, shortly after the launch of iTunes new release, Apple's Steve Jobs expressed his belief that ads will be "tagged onto" podcasts. But what does "tagged onto" mean? At first I thought he just meant ads would be part of the podcast, as they are now. But what if he's thinking of attaching a third party ad to the beginning of the podcast, something not produced by the show creator but which Apple would force to be played before the show proper started, much like video ads play before videos on CNN.com? An advertiser is sold space by Apple, who places the ad in front of the podcast in this scenario. Media buyers might be wary of dealing with some producing a podcast from their den but buying ad space from Apple is a no-brainer. It will be interesting to see how this turns out.