I’ve just implemented a feature I’ve long wanted on many news aggregation sites: story merging.
Stories that are similar without enough new content (like general news sites all reporting on the same story) can now be merged into a single story rather than being downvoted or deleted, while preserving comments made on them and still working with the duplicate detector and other things.
When a moderator merges a story into an older one, it:
For example, a news article about the Heartbleed Bug has been merged into the original story for the bug. Visiting the first link automatically redirects to the original story and the one comment that was made is visible there.