I just finished reading a few articles about using wikis in a library setting. I'm not sold on the idea yet. The wikis that I've seen (and maybe I just haven't seen enough of them) are kind of dull and messy. I prefer flashy websites with some authority. I would rather develop patron relationships via a blog on our official website.
However, I do like the idea of using an internal wiki to communicate with coworkers. It's so easy to get lost in email conversations. With an internal wiki, we could all be on the same page.