Deduping blogspam and re-reporting of AP/Reuters, and using that redundancy to uprank the original source, is something Facebook should have been doing a decade ago.

It should be more akin to https://techmeme.com (or hn for that matter) where they editorially try and choose the first or best source. If a better source becomes available they swap. Facebook could benefit from this dynamicness, where a story can bump and replace an existing post.