Podcasts are very different from blogs, even though both are generally labeled as user generated content,
Consuming information from podcasts can take longer than from blogs. As Don Dodge points out in The problem with podcasts and web video, "I can easily plow through 100 blog posts in an hour or so. That is just not possible with audio or video."
This is especially true when trying to perform target-oriented research. Trying to extract facts or structured information from podcasts is tedious, and totally ineffective. It is much more effective to do so on the written-word web (though I would be cautious about relying heavily on blogs as a factual information source, for separating fact from opinion and fiction can be hindering).
But venue should also be considered. It is much easier to consume podcasts than blogs while excersing or commuting, especially when you happen to be doing the driving. I like to think of podcasts as the TiVo or VOD of user generated radio, and as such it shouldn't be compared to written blogs, but should really be looked at in light of the alternatives at that venue and time. To me, podcasts are often more interesting than broadcast radio – I can listen to my favorite tech show at my convenience instead of what happens to be on the air at that moment in time. Podcasts are also more lively and updated than most audio books, as they are timely and typically represent a wider spectrum of opinions and voices.
However, the real revolution podcasting brings is the ability to virtually attend conferences and events that one wouldn't otherwise. Listen to keynotes at TIEcon or TED from the (dis)comfort of the treadmill (heck –do both TIEcon west AND east). Hear tech entrepreneurs deliver their presentations at conferences across the globe, and form an opinion about their vision based not only on the content, but also on the drive, passion and sincerity as projected in the tone and quality of their voice. These are qualities that go beyond the written word and can only be experienced via the spoken word, be it audio or video.
Discovering content and finding specific information is difficult with podcasts. There's Podzinger (based on BBN technology) that transcripts podcasts, and lets users search the transcripts and listen in, right from the point where the searched keyword was mentioned. Other companies let users create their own channel, essentially an aggregate of podcasts, letting other users listen to a pre-selected batch of shows on similar topics of interest that cater to similar tastes. But these are no match for discovering and extracting information from the written web. Also, getting to the gist of a podcast discussion takes longer than looking at a search results page and clicking away to the desired information.
I also agree with Don that podcasting will be much less pervasive than blogging (I disagree on video though: I think the current numbers already show scale, and IMO we are now just scratching the surface).
And that is actually the good thing about podcasting. This lower pervasiveness, and the fact that there is an inherent barrier to content authoring and creation will actually make the podcast long tail significantly shorter than that of blogs. Unlike blogging, podcasting is not 'generatable' anytime/anywhere. The time, effort, and somewhat of an investment required to create a podcast will make the people who are less passionate about it much less persistent, and hence much less likely to go beyond initial experimentation. This shorter long tail will offer less noise (a smaller, more 'pro'esque variety of shows), while retaining the long tail characteristics (shows targeted at small niche audiences not available through broadcast/digital radio). And this is the agent that compensates for the limitations of the format.
Just my two cents on podcasting.
