Why not just redirect to Stack Overflow?
Maybe heresy but SO does all of this so much better – why not just redirect questions to that site?
SO has a strict question-answer rules. This here is a forum. There's a lounge area, job offerings area, national sections etc. You can discuss ideas, throw around loose designs. You can talk about whatever you want, not just ask strict questions. It's true that questions are majority of topics but still, there are occasional many pages long discussions that would be quickly down-voted on SO.
The other thing is having everything Qt related in one place is a good thing. Having a community spot next to a download page etc. keeps it all nice together.
This is just my opinion. Nobody of course is stopping anyone from using SO for Qt questions. If you can solve your problems by getting answers there then cool. To each his own.
I agree that SO is pretty much antithetical to community but it does the QA part (along with search, suggestions, formating, etc.) so well. I've often posted the same question both here and there, which is tedious.
The "having everything together" idea really means little with linking – better to aggregate the best: SO for QA and forum.qt.io for community, chat, etc.
(Of course I expect no change and only posted in exasperation t having to copy and paste my questions here over to SO and vice versa)
Well, the same problem is true for pretty much anything on the internet. Fragmentation happens and will happen.
I might be wrong but I don't think that logistically and (probably) legally integrating SO into the QtProject in any way would even be feasible.
Btw. Cross posting here and on SO is not a nice thing to do IMHO. I'd ask in one place and wait for an answer. If nobody answers I'd ask somewhere else. Like in offline world. You don't ask one person and then turn your back on him and ask another while he was still thinking. Just not polite. But that's just me. Less garbage in the internet, less people's time wasted, less trees being cut etc ;)
Well, fragmentation is the issue – I'll post here because it is the "Qt forum" but often receive few replies – so I'll post at SO. It would be less fragmenting if what QA energy is here were redirected to SO. (Back in the day, "cross posting" was considered bad etiquette but it doesn't seem like people care much these days.)
SO is CC licensed – and linking to Qt sections there, and directing users to post questions there is certainly "legal" (in my IANAL opinion...).
Anyway.... not going to happen
You pretty much have the answer to your question there.
SO does not help one bit in keeping a community together. Also fragmenting the services does not help in that (Q&A in SO, other things here), and people would probably still cross post to both (or shout for a Q&A area here).
I don't see having multiple Q&A forums an issue (there's Qt centre, Qtforum, Qt apps, Qt developpez, Qtfr, and other local sites too). The thing we try to do here, is to be a place where the community can come together, talk and ask questions among other things.