Chris Bowers over at MyDD takes on critics of MyDD as a blog, and in the process makes some really good points about what blogs are good for, what the mass media is good for, and what to expect each to do. There is a great deal of good food for thought there.
This is particularly true if you are attempting to use the internet for specific commercial, political or other purposes. Blogs appear to be a method of providing information to a niche market. After that they will sell something or influence people to do something. To do that they need to provide regularly changing material of interest to the market they are focused on, so that they build repeat viewership.
Go read Chris' article and see what you think.