Perhaps I don't understand in what setting you're referring to the use of video?
Are we talking in-line embedded in websites? Like on NASCAR.COM? I assure you the majority of viewers
hate the inline forced/pushed video on that site. It loads heinously slowly, it doesn't play smoothly, and it makes browsing the site from work a total no-no (the audio causes the "straying" employee to get caught red-handed!). Spend 10 minutes on their forums and you'll get an eye-full of annoyed viewers. I have many racing-fan friends who refuse to go to the NASCAR.COM site now because of their abuse of audio/video.
Now if you are talking in terms of something like podcasts that they can download at their choice? That are universally accessible (format that both Windows and Mac can view, such as within iTunes or on an iPod Video)? In that case, my experience says "cool,"
except!!!... Except that you must have a
purpose for using video. Don't abuse the medium. If you are selling something that
must be visually demonstrated and can only be fully appreciated by being seen (e.g., the beautifully shiny restored paint job on the '57 Chevy), then yes, video makes sense.
But as an iPod Video consumer, I'll tell ya' -- don't waste my time with videocasts that don't show me anything I needed to see. If it is just as well presented in audio-only,
use audio.
As a side-note, I also recommend offering a printed transcript with your audio & video items. Not all media players are "stable" on all OS's. And, there are some of us who don't learn squat from audiocasts. We simply need to read in order to assimilate. I bought one of Yanik Silver's products which offered a printed transcript of his audio files, and I was extremely appreciative of this... I can really dig into the PDF, instead of being forced to wrestle my finicky Real Media player on OS X.
Hope this helps!

Bailey