Originally Answered:

How does Quora combat duplicates of other questions and answers?

Dupes of answers: Quora does nothing to prevent us, and God preserve us from the day when it does. Bots unleashed to collapse answers left and right, muttering “this answer has three words in common with the next answer. Exterminate! Exterminate!”

Dupes of questions: Quora has conflated the search bar and the question bar, in the hope you’ll notice as you’re typing that similar questions have already been asked. Quora also displays similar questions in the sidebar, which triggers users to merge them. Both reasonable actions.