This post is based on reading an article on the increase in time people spend reading content. The article link is here: http://news.yahoo.com/s/nm/20070813/tc_nm/internet_study_dc_1
Now, my own personal opinion is that video content is very time consuming. Although it may be the easiest to digest, it is the most inefficient and getting information. Most of this blog is about getting information, not about entertainment purposes.
If you are reading this blog -- you probably speed-reading and just skipping most of the fluff to get some key pieces of information. That is good -- that is how it is suppose to be.
Video/audio content, however, you do not have that option. Written works have no time component, only an 'order of content' component that you can filter through quickly. However,
Video/audio content DOES have a time component meaning you are limited in efficiently digesting/absorbing information based on the time component established by whoever created the Video/audio.
I personally think podcasts/webcasts are one of the worse ways to send out information (good for advertising/entertainment, but poor for sharing information). I pretty much never watch a podcast/webcast for information -- instead I'll Google for a text version and read through that instead.
Now, that is just me - there are people/audience that do prefer video/audio content for getting information. And, I might be one of those people...if I didn't have to worry about time ;-)