Have an evangelist
If your blog is going to be successful, it needs to be treated as such within the institution. It needs a person that understands the potential, can encourage people to post and generate enthusiasm. In our institution we casually do this by suggesting blog entries to people. The editor of our calendar magazine, Paul Schmelzer, also suggests stories to various staff and collaborates with them.
Set up guidelines
Staff may have an idea what to post about with regards to their area of work, but a set of guidelines about grammar, style and other institutional rules can prove indispensable for quelling questions people may have about blogging. See also: Walker Blog Guidelines
Hold people's hands
A lot of people have trouble with understanding the mechanisms of blogging, not to mention computer use in general. Draft and distribute a howto document to would-be bloggers to show them the steps. Most of the questions you'll probably get will deal with formatting and dealing with media. This means you may have to have an open phone line. If we had to field a call for every post on our blogs, I'd gladly do it (sometimes it seems like we do!).
Show them the money
Using the information we've shown you in our stats section, track your stats rigorously. If your stats play out like ours, use them to entice your staff to use the blogs as a promotional outlet for their programs. Have any success stories? Flaunt them.
Bring in some fresh blood
Consider bringing guest bloggers or outside voices to participate on your blogs. Do you have someone who makes a lot of comments and appears to be an avid reader? Invite them on board for a few posts.
See also our notes on this topic from MW2006: Getting People to Want to Post