The ability to link cross site duplicates
I'd like a "close as cross post" option that allows me to provide a link to the question on the other site that was cross posted as. Either that or have duplicates work across sites.
Tim's proposal no longer relevant close reason is fine, but I don't think it goes far enough. Cross posting is a significant problem that we deal with on at significant portion of our questions on U&L. We are constantly closing, migrating and linking to FAQ's about it.
First of all I would propose that the SE software run an automated quality check on the post to make sure it isn't an exact match or even similar match to another open question by the user. They often post a day later with a a few tweaks made, but the majority of them would be easy to match. Only questions without accepted answers should be considered.
Secondly the close-as-duplicate really should allow off-site links, or there should be a target close reason that specifically explains that cross posting identical questions is not ok. A one step migrate/merge might be the answer.
I don't favor attempting to eliminate cross-site duplicates. Finding duplicates on a single site is hard enough as it is. Our experience with invalid question migrations suggests that the community is either unable or unwilling to accurately police itself in this way.
There's nothing wrong with cross-site posting, provided that:
Questions that are on-topic on multiple sites are very rare. In practice, if it does occur, it will generally be on-topic on no more than two sites.
We need this for the new users who don't understand that cross posting isn't acceptable here.
The solution is to modify the