I have to say that I agree with this more than disagree with it.
While I have, to some degree, a vested interest in promoting blogging, considering what I do for a living, I do think that it works for some and does not work for others. Corporate culture has a lot to do with it.
Increasingly, I think internal blogs for corporations might be extremely beneficial, but external blogs maybe less so. I think corporations will probably head in the direction of having third party bloggers they ally with. That way there is plausible deniability if the blogger goes off the reservation.