I think video has surpassed audio as far as web 2.0 prosumer content thanks to YouTube.  While you still can’t tag a certain instant in a video or directly quote it through an excerpt clip like you can text blogs, YouTube makes video blogging a two-way street by allowing viewers to instantly reply by capturing video online directly from their webcam at home.  No fuss, no mess, no Windows Movie Maker.  I think this development actually hinders the evolution of audio blogging because I’m sure a lot of people prefer the visual medium to audio because it adds a dimension of personality to the content they’re taking in.  I hope audio catches up.