In Need of Group Blog Wisdom

Yesterday, at one of our faculty development sessions, we decided to start a school-wide blog, where faculty can exchange ideas for how to inject more creativity into their classrooms. We're going to set it up with Blogger, which will let us have 100 users. I think we only have 300 or so faculty members, many of whom want nothing to do with one more technology application, so I don't think that will be a problem. People who only want to post once a quarter or so can just forward their postings to me (yes, I volunteered to be administrator), and I'll post them. People who want to post more regularly can sign up as members. I plan to have the blog open to anyone, who can visit and post comments (which I'll delete, if they're icky). So, students could read and comment, but only faculty would be posting (would administrators and staff want to post?).

I'm wondering if anyone has experience with group blogs that are made up of users that are bound more by their institution than by friendship or family bonds. I'm in search of good ideas, cautionary tales, any wisdom that the blogosphere has to offer.