I have been following a rule when I decide where to ask a question. I think the process is like this:
If I think the problem has a definitive answer, and is based on something that has been definitely achieved then I will ask on SO because the answer is likely to be succinct and helpful for others. E.g. How to count missing in a vector.
If the question is more exploratory, like how do I do machine learning? Then Discourse is better.
Interested in others thoughts to flesh this out.
The community that has formed around Julia is one of its best features and it seems to be most active here on discourse, so if I have a question or discussion topic at all related to Julia, I always come here.
i have to add, in Juliaās slack, there is a bot that adds every SO question with the Julia tag, so we are aware of new questions 
Is there a channel where these questions appear?
in slack, #stackoverflow-feed
I like the discourse community feel a lot more than I like the feel of StackOverflow, but SO is more familiar to many newcomers and is often more āgoogleableā, so I try to at least answer questions in StackOverflow and occasionally crosspost questions from Discourse and Slack to SO.
Interesting question. I definitely have a rule, but I never stopped to consider what that rule is.
I think it is something along the lines of āhow generally applicable is this issue?ā. If it is something a lot of people might encounter, then it goes on SO. If it is potentially specific to me, then I come here. But for sure there is a grey area in the middle thereā¦
I donāt really have any good reason for why this is my rule thoughā¦ perhaps it just reflects that more people, and especially more newbies, are likely to turn up on SO.
I would prefer here on Discourse (on SO I find sometimes people closing legit questions for a questionable attempt to keep a good āquality standardā of the QA platform).
But then, if we all post here, Julia will drop in the next (biased) statistic of programming language usage based on SOā¦ biased and not even consistentā¦ better the community, less the rank of the language :-/
Iāve never posted a question on Stack Overflow because I donāt have time to write a formal analysis of the problem that is required to avoid being heckled.
I would like to see this Discourse archived and optimized for search engine, like
Just some ideas.
I have the impression that the preferred style of questions on StackOverflow is about problems which are very concrete, pragmatic, and well-defined. Which is fine ā those criteria can help focus discussions.
But at the same time, Julia is a language that is breaking new ground and exploring novel ideas and concepts all the time. While the ācoreā language is more or less settled now (for 1.x), best practices are still evolving, new ideas are experimented with, and hypothetical discussion or speculative requests for advice are always welcome on this forum.
Also, a lot of contributors here have a pedagogical approach and pay attention to writing clean code, being ready to explain why something was done in a particular way. Even reading discussions here I donāt directly participate in is very educational.
Moreover, since there are a lot of domain experts hanging around, it is not unusual to receive great advice on linear algebra, statistics and probability, differential equations, optimization, and a lot of other topics which are not strictly about the language or its libraries, and would be very likely to be marked off-topic on SO. Amazingly, this while a lot of this is off-topic it is mostly self-regulated by polite people so it does not get out of hand.
So after doing some research (to avoid asking trivial questions if possible), I always just ask questions here and donāt even consider SO.
A (somewhat nasty) trick in SO is just to add the Julia tag, as adding other tags attracts moderators from other communities with the SO mentality. i have seen a lot of somewhat valid SO questions get closed because they tagged #mac and a mac moderator came and declared the thread offtopic, where there is high posibility that an SO question with a julia tag would be answered by people of this community, Discourse style if it is needed.
I donāt know if its doable at the level of Juliaās Discourse of it requires modifications of the Discourse Software itself. but there are good ideas. For example, there what an attempt to port some questions from Discourse to SO( i know there is a template somewhere)
I tend to go to Discourse or Slack for questions that might be a bit specific for the specific problem Iām working on or if Iām not sure that a ābestā answer would exist. However, Iāve tried to put questions that should have a simple or consensus answer on Stack Overflow.
A few reasons for posting on Stack Overflow:
Even though I consider myself relatively inexperienced, I know Iāve come a long way from trying my first programming tutorial. For me, Discourse and Slack might be better but I still think of when a question I have now might have helped me from several years ago. Thatās when I tend to prefer posting on Stack Overflow.