I keep getting asked this question by colleagues here at RIT and elsewhere, and I find myself sending them the same links over and over again. So here's what I give people who ask me this, in an attempt to clarify the value of blogging to those of us in academia. It's not all about personal confessionals. Really.
Why I blog
The Academic Contributions of Blogging?
Academics and Blogging (see the comments)
Academic Blogging and Literary Studies
Lit Studies Blogging, Part II: Better breathing through blogging
Jill Walker and Torill Mortensen
Blogging Thoughts: Personal Publication as an Online Research Tool (PDF)
Blogging @ MEA (Collin's notes from the panel that I did with Seb Paquet, Alex Halavais, Clay Shirky and Jill Walker)
University of Minnesota's edited collection of essays, "Into the Blogosphere"
Feel free to add other favorite links to the wiki page I've set up.