Maybe a little bit esoteric, but I like to throw these things out there.
On occasion, I'll post something, someone will quote me and respond, but then the thread will carry on for five pages before I get the chance to look at it again.
It would be nice if there were a little button I could click that brought me to the search engine and showed a list of all the posts which quoted that one specific post. So I could see where that little side discussion has gone (if anywhere).
So in the same way that the "find all posts that quote seamus" function looks at the <quote> tag to search for where it has "=seamus", this one would look at the part of the quote tag that has the post ID in it. You click a tiny icon then beside the "Originally posted by joebloggs" (just like the icon which brings you to the actual post), which shows you the list of posts which quote this one.
Obviously doesn't work for manual quoting, but you can't win 'em all.