Why can't non-research level questions simply be posted on mathoverflow with a special tag? Then people who wanted to answer MSE-type questions would just limit themselves to that one tag. I am asking purely hypothetically, of course, as I know the sites work well the way they are.

  • $\begingroup$ Also, why two CS sites? $\endgroup$ Apr 5, 2015 at 20:30
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    $\begingroup$ Compare the volumes of questions at various levels. You will find that the lower the level, the higher the volume. If anything, many users would prefer three math sites: one for high school/freshman(sophomore) levels, one for advanced undergrad/early grad school, one for research level (including advanced grad school). $\endgroup$ Apr 5, 2015 at 20:33
  • $\begingroup$ @JyrkiLahtonen But why can't they just be separated by tagging? Or maybe something stronger, but still sharing one domain name? $\endgroup$ Apr 5, 2015 at 20:35
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    $\begingroup$ The volume of easy questions would drown everything else. Anything stronger would need major changes to the software. Also the reputation scores would need to be separated. $\endgroup$ Apr 5, 2015 at 20:38
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    $\begingroup$ Why so many sites? Why not use just one site "StuffOverflow"? $\endgroup$
    – Asaf Karagila Mod
    Apr 5, 2015 at 20:53
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    $\begingroup$ As you want to know why something can not be posted on MO you should rather ask on meta.MO not here. $\endgroup$
    – quid Mod
    Apr 5, 2015 at 21:17
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    $\begingroup$ M.SE is well-geared for pedagogical purposes & curiosity. MO is good for answering inscrutable messes of symbols with more arcane notation. There are clearly well-defined areas for each site. $\endgroup$ Apr 5, 2015 at 21:51
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    $\begingroup$ I disagree with the downvotes on this question. It may not be immediately obvious to a new user why there are two math websites with such different scopes and user bases. For example a new user may not even know that MO didn't start out as part of the SE network (though a Wikipedia search would have clarified that). It just looks like a general curiosity question, not a proposal to merge the sites... (Cf. the last sentence) $\endgroup$ Apr 6, 2015 at 8:44
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    $\begingroup$ @Najib: What about downvoting for the way the question is written, and more than that, for the lack of search effort on meta? For example, meta.math.stackexchange.com/questions/11329/… $\endgroup$
    – Asaf Karagila Mod
    Apr 6, 2015 at 8:53
  • $\begingroup$ @Asaf I partly agree, but here the OP seems to be aware that the two sites are for different kinds of questions, while the answers to the dup mostly say "There are two sites because they are for different kinds of questions". I think Tim Post's answer is a reasonable explanation for the follow-up question. (TBH, my first reaction was a downvote for the reasons you mentioned, but then I reconsidered. It's just that meta can be so negative sometimes...) $\endgroup$ Apr 6, 2015 at 9:08
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    $\begingroup$ @NajibIdrissi it is weird to ask the question as written here; perhaps non-intentionally it comes off as provocative. $\endgroup$
    – quid Mod
    Apr 6, 2015 at 9:18

1 Answer 1


While the topics are different, a blog post that Robert wrote some time ago explores the reasoning behind 'splinter' sites, and under what reasons we'd support them. There are also technical considerations to speak of, MathOverflow was an autonomous SE 1.0 site not connected to the Stack Exchange network in any way for a very long time. They've been part of the network for less than two years now.

We'll get back to that later, let's talk generally.

It's not just math, why do we need:

.. it comes down to showing enough interest, support and expertise in a topic along with reasons that it clearly wouldn't work as well as it could as a tag in another overlapping subject.

People that use MathOverflow are purely interested in research-level stuff, and while tag filtering does work well enough to keep out 'noise' - there are some other things to consider:

  • Communities need to agree on how they're going to handle certain things, elect their moderators, and use their votes to keep the site healthy. When you have two distinctly different groups of folks sharing the same roof - this gets difficult.

  • We need to be able to promote and encourage sites as a single community. This is very difficult when you have two groups with distinctly different needs, goals and preferences.

We prefer not to fragment groups of professionals or academics when it's clear that they have much more in common than not, and we're very careful to not do so unless it's a clear necessity.

Now, going back to MathOverflow - there's no way they would have joined the network as part of a more rudimentary site, it's just not in their topic scope at all and the experience would have been awful for everyone involved. So, let's pretend that MathOverflow was born out of Math SE users saying "We do research level stuff, and I need a place where everyone else participating is doing the same thing in order for that place to be useful to us." - we would have agreed.

I love our coffee site. Even though I'm an avid home cook, I like pulling a double shot of espresso, sitting down and seeing a front page entirely about coffee, it makes me want to talk about coffee even more.

And that's why we do it.


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