In case a user asks the same question on two different SE, it would be great to automatically warn the readers that the question has been cross-posted and give a link to the cross-posts.

The motivation is twofold: making cross-posting abuses easier to detect and avoiding answering a question that has been answered on a different SE.

marked as duplicate by user213963, ɥʇǝS, gnat, Aziz Shaikh, Martijn Pieters Sep 26 '14 at 6:48

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