@FrançoisG.Dorais the link seems missing @FrançoisG.Dorais

@François Dorais and @Martin Sleziak, thank you for your work on the data explorer queries. These could be very useful.

@Martin Sleziak: When I asked about detecting duplicate questions on Math.StackExchange and MathOverflow, I was thinking that we could take more systematic action on such posts. For example, we could notify the people asking such questions soon after they are posted, and even close or migrate the duplicate questions. The data explorer queries you and François Dorais gave above could be very useful for such a purpose, despite the approximate two day delay in the data available.

What do you, and others, think about taking such actions concerning these questions?

@RicardoAndrade After your post in this chatroom, I was thinking about creating a suitable template in the List of comment templates on meta.MSE.

It should explain that a user should wait some time before posting to another site and they should definitely include links to posts to other site.

It might link ti Moderator Supported (Official) Guidelines for “Legitimate” CrossPosting?

This might be also suitable candidate for such template; Is cross-posted forbidden/discouraged on Stack Exchange sites? If so, why?.

Or maybe some other questions tagged cross-posting.

Speaking of this, MO does not have something like List of comment templates, does it?

Although I am not sure to which extent would some of those types of comment useful at this site.

@Martin Sleziak, as far as I know, there is no list of comment templates on MathOverflow.

Perhaps that is something to consider?

Perhaps. (That's why I've mentioned it.)

@MartinSleziak, do you have an opinion regarding possibly taking more drastic action, such as closing or migrating the duplicates?

If the question does not belong to MO, the MO most probably will be closed or migrated anyway.

I mean even without checking whether it is a duplicate.

Of course, migration is option only for post not older than two months (IIRC).

What if the question is appropriate (or perhaps borderline) on MO? Should it then be migrated out of Math.StackExchange?

I am not sure about that. But I certainly agree with this: If you cross-post ... indicate clearly in all copies of the question that the question is cross posted (and link to other copies).

From Willie Wong's answer.

I completely agree with that answer of Willie Wong.

@quid: First of all, I want to congratulate you on the awesome and thorough job you have done with the tag 'topology'. I am sorry that I did not help much with that. I also wanted to ask you how you want to proceed now that the retagging of the tag 'topology' is approaching its final stretch. Do you still want to retag (nearly) all remaining questions which do not have either of the tags 'gn.general-topology', 'gt.geometric-topology', and 'at.algebraic-topology'?