Sometimes I search for a specific information inside of a story. e.g. the number of boyfriends the main character had till now. I have a copy of my own stories/threads as text-files, so if the information is from me, I have no problem with it. If the information is from another writer, I have to go around and search it by hand. So I could imagine a full text search function, which would only work for a specific story or a thread with all parents up to the beginning of the story. Search results could be shown with a small preview (e.g. 10 or 20 words before and after the search term) The number isn't shown, but probably findable in result 2 If performance would be an issue, that could be limited to user, who already contributed to that story.
This would be rather useful for authors contributing to larger stories, especially if the work isn't all their own.