A whole bunch of links that I have accumulated over time. Here they are:
Andrew Sullivan in The Atlantic: Why I blog.
Daniel Drezner: Public Intellectual 2.0.
Dan Cohen: Professors, Start Your Blogs.
Jessica Wapner in Scientific American: Blogging -- It's Good for YOu.
Steve Yegge: You should write blogs.
Janet Stemwedel: Why would anybody want to blog under a pseudonym?
Not specifically on blogging, but still: Michael Nielsen on Five problems with doing research in the open.
Shelley A. Batts, Nicholas J. Anthis, and Tara C. Smith: Advancing Science through Conversations: Bridging the Gap between Blogs and the Academy.
Simon Owens in MediaShift: Econ Bloggers Gain Clout in Financial Crisis