What did you find interesting?
I found the fact that all these libraries and librarians are really working hard to figure out how wikis can be used in all sorts of ways in the library pretty interesting. The SJCPL subject guides really knocked my socks off - the idea that any librarian can add content and any user can comment with more information or to clarify/correct information was pretty cool!
What types of applications within libraries might work well with a wiki?
Obviously, the subject guides seem to work well, and I've heard of entire library websites being built with a wiki, but I think smaller projects will work best. The concept of the staff or internal website being wiki-ized (did I just coin a word?) is pretty cool - seeing as how I set one up for us... The more people who feel empowered to add content, the better, in my opinion!