I'm jealous, you're a librarian (I've one more year left in my MLIS program)...
I noticed the same thing about the tags. So many people will tag the item with things like the author, personal details (i.e., "own" or "read"), as opposed to themes, subjects or other meaningful tags (on the global sense). I kind of wish there were a way to separate the tags so users can have personal tags and public tags. I just try to do my part and use only globally meaningful tags that will help me and anyone else trying to select a book.