Well, it sounds to me like there's a question for contextual filtering on the active sidebar based on user prefs. (e.g. block this thread from appearing on *my* active sidebar for 1 week, 1 month, forever, etc.) - the time limit is to help with benny1967's thoughts (with which I concur) re revisiting threads later. A pop up of a previously barred thread might re-spur interest...

Thing is, I have no idea how to do that, or even if it's possible. Perhaps a brainstorm idea...?