Allow linking to duplicates on other Stack Exchange sites for popular closed questions
97199
The ability to link cross-site duplicates
148042
Help users create dummy links that are not to unrelated commercial sites
37728
How do I vote to migrate questions to other SE sites that aren't listed?
82191
What happened to the link to the duplicate when a question is closed as a duplicate?
3685
Confirming that my own question is a duplicate by voting to close should have immediate effect
38594
Don't automatically edit the post to insert "possible duplicate" links
133887
Are questions closed as duplicates ever automatically deleted?
34703
Questions linking to external web sites instead of showing code
77168
Do related linked questions really need to be linked twice?
111647
How to find questions closed as duplicates via the Data Explorer
102324
Provide a link to per-site Meta
47803
Answering the same question across the site
106952
"Please ask a new question" encourages question repetition for duplicates
128805
Is there an easy way to replace duplicate files with hardlinks?
22458
Add ability to flag answers as duplicates
30978
Parse question links from other SE sites
39363
Please provide the ability to cross post questions to multiple Stack Exchange communities