In a podcast interview with John Furrier, Forrester Research's Charlene Li explains that the comparatively low numbers of people reading blogs, listening to podcasts and subscribing to RSS feeds is only a precursor to their coming wider acceptance.
As their use becomes more seamless to the audience, I think this is true. The fact that your browser doesn't do everything for you yet is a major impediment to the popularization of these forms of information exchange.
Update: I didn't have her URL handy earlier, but now I'd like to tip my hat to Donna Papacosta of Trafalgar Communications for the link.
Photo of Charlene Li courtesy Forrester