I posted this to the NNTP forums last year before I was a Logos customer myself, but now that I am, I want it even more badly than I thought I would.
That is I want verse/passage tagging that works like, say, Delicious.com tagging.
I'd like to be able to select passages and "tag" them with topics of my choosing then be able to search by my tags. For instance, find all passages that are tagged with "humility" and "examples". A friend has explained how Notes and Clippings can sort-of fulfill my use-case, but they're an imperfect substitute.
Optional features would include a clickable tag cloud and a separate window which would show all the tags for currently visible passages.
I do see a couple other posts here with what appear to be the same suggestion, but I thought I'd resurface it with my specific "requirements". I'm so accustomed to tagging and find-by-tag that it's now difficult for me to use any kind of large information repository without it.