Detection at submission time
As someone types a title, similar existing posts surface underneath it. Most duplicates never get created because the submitter votes on the existing post instead — which is also the outcome you want, since it concentrates demand signal.
Merging after the fact
Merging moves votes, comments and followers from the duplicate onto the canonical post, then leaves a redirect so old links keep working. Vote counts are de-duplicated per person, so a user who voted on both is counted once.
- 1Open the duplicate post.
- 2Choose Merge into and search for the canonical post.
- 3Confirm. Followers of both posts now receive updates from the canonical one.
Merging is reversible for 30 days
If you merge the wrong way round, unmerge restores the original post along with its own votes and comments. After 30 days the merge becomes permanent.