How do I tag books in CloudReaders? I have the CloudReaders app on my iPad.  According to its release notes and other reviews of it, it supports tagging of books to allow for filtering.  However, for the life of me I can't figure out how to do it - only how to search based off tags?  Does anyone know how?
After another 30 minutes of playing, it turned out (competely illogically) the reply/share button leads to a tagging UI.