Writes Scott Rosenberg in Salon  in a very balanced article on the debate between bloggers (amateur journalists) and pros (professional journalists):
Blogs can do some things the pros can’t. For better and worse, they air hunches and speculations without the filter of an editorial bureaucracy (or the legal vulnerabilities of a corporate parent). They trade links and argue nuances, fling insults and shower acclaim. The editorial process of the blogs takes place between and among bloggers, in public, in real time, with fully annotated cross-links. This carries pluses and minuses: At worst, it creates a lot of excess verbiage that only the most fanatically interested reader would want to wade through. At best, it creates a dramatic and dynamic exchange of information and ideas.
Blogs are only as good as the person writing the blog. Blogs are about people, in most cases, a single individual with views to express. Bloggers may lack the variety and breadth of mainstream media, but they do have depth in specific topics which they use to articulate their viewpoint and present a lens on the world.