Today, I checked out BlogTV at http://www.blogtv.ca/LiveNow. The media appeared to be used by single people to send messages to each other. The young girls smiled a lot and flirted with their eyes. A young guy tried to make profound comments about creating his own world in this life and the next. However, he paused many times to put his thoughts together and rambled along in half sentences. None of this produced interesting material for a blog, video or not.
Talking into webcams seemed to make people look lonely and in need of friends, attention and/or love.
To me, a blog entry has to be carefully thought out and expressed. I'd have a hard time doing that in front of a camera without notes. Of course, if I had notes, why not write them down. That's what I want to communicate.
I've written over 1100 blog entries in four years and I've never felt the need to present this material over a webcam to YouTube or BlogTV.