Obviously it would be active for team members only since it could also be used as a round about search function if active for non team members

But during typing in the subject it searches and displays existing threads that might be similar or shows possible duplicate existing threads after submitting but before posting as a chance to cancel your post before creating a dupe.

The live subject dupe search would list out current thread titles for the last 7 days that match two or more words that the new subject contains.

Awesome!  :-)