The thing I liked about Library Thing is that after tagging only six books from my personal library, I found other people who had the same ones in their lists. It made me want to add more to see if the same people kept showing up. Sure enough, I added six more and the same person I had seen before, NancyLH, had eight of the same ones. So, I'm going to take a look at her list and see if I find some good titles there. Looks like we have similar tastes in books.
We use AquaBrowser at our library which attaches LibraryThing tags to the titles in our catalog. Possibly, this could be used for book clubs. A good way to share lists with each other.
I can definitely see a use for LibraryThing Local. We could add our book related events--for example, our fantastic Friends of the Library Booksale.