The 7 April edition of the Chicago Tribune has an article on The Becker-Posner Blog, written by Judge Richard Posner and U. Chicago economics professor Gary Becker, which does a nice job of talking about why blogs can be valuable: immediacy, write what I want, comments, informality. What I found refreshing is the article's focus on the value blogging is bringing for intellectuals.
Chicago Tribune article by Maureen Ryan, Smart bombs, Tempo Section, 7 April 2005. You may need to be registered (free) to get at the article.