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Cross-posting on StackExchange sites

Is the posting of conceptually equivalent questions on different Stack Exchange sites discouraged?

I am asking for an official answer on this, because I was surprised at one of the answers to a different question: Should there be a way to search all Stack Exchange tech sites for potentially overlapping questions? . It seems like a strange position for SE to advocate duplication across its sites, and makes it unclear why we have all these other small sites.

I also found a post which seems to argue that it's not even permitted ( Is cross-posting a question on multiple Stack Exchange sites permitted if the question is on-topic for each site? ). I don't think it's a duplicate though, because there's a difference between posting conceptually equivalent questions on multiple sites and cross-posting an identical question.

  • Notice that the answer you are referring is talking of two users who ask similar questions on different sites, not two users who copy-and-paste the question of each other on different sites, or a single user who asks the same question on different sites.
    – apaderno
    Oct 3, 2012 at 18:48

3 Answers 3


Yes, cross posting is verboten.

Cross posting messes up the migration process - just ask the moderators on Programmers...

"conceptually equivalent questions" is a bit too vague in my opinion - if it is the same question then it should have one home and one home only.

If it is a different but related question that happens to have a better home at a different site (or just happened to also be on topic on another site), then that's fine.


Short answer: Yes, it is discouraged.

The reasoning being, 'conceptually equivalent' questions are likely to be on one topic or the other. If parts of a question apply on each site, then the question probably needs to be split up into multiple parts, and each part posted appropriately.

But I don't know if it can be said anyone 'encourages' this behavior at all. Very few people are going to see the duplication, so each post will be considered in isolation - and that's how they should be considered.

If a post is more on topic another place, it should be moved there, or closed so it can be reposted there.

But when we are not talking about equivalently-worded questions, it can be impossible to always come to the same conclusion from multiple sites.

Worded one way, a question might seem quite appropriate for Stack Overflow. Worded another way, the same question might seem appropriate for Programmers.SE. Each should be judged alone.

  • We do see questions that are properly formed, well focused and still valid on both physics and chemistry (or physics and astronomy while that site lasted). We've been encouraging users to try one site or the other first and give it some time. Oct 3, 2012 at 19:00

It is (strongly) discouraged to post in close temporal proximity on different sites.

To be a little more complete, the correct procedure for cross posting is

  1. Reject outright posting to any site where it would be off topic
  2. Take your best guess at the best site you haven't tried and ask it there.
  3. Attend to any comments and make sure that your audience really understands the question.
  4. Wait for at least a full day, two would be better (especially if there is a weekend or holiday involved).
  5. If you haven't gotten the answer you want consider returning to step 2. and add link to the earlier version explaining why it failed to meet you needs and why you think that this new site might be better suited after all.

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