There's a reasonably good post today on the Better Health blog about why health-care professionals should blog. While I don't agree with some of the points in the entry (content is not king because it isn't a sustainable competitive advantage), some points are very thoughtful ("don't confuse size with importance"). It is also very encouraging for novices:
If you aren't blogging there is still a voice that needs to be heard. What exactly do you bring to the discussion? You! No one has had your experiences or can express your opinions. More importantly, no one else can bring your voice. And unlike a meeting or an email, there are no time limits or physical boundaries to the blogosphere. There is room for everybody, and that means you!