Here's the two examples discussed in this post:

An excellent reference point here is the Unity3D forum (at answers.unity3d.com)

(I am or was a top ten member.)

Unity is very important commercially as it is now the main game platform, and the "answers" site used to be fantastic -- and indeed, very important commercially. Since, like many companies, Unity's stance was "oh, uh, we offer utterly no support because ....... we offer a Forum!" (Fair enough, it's a commercial decision.)

It's now complete crap and everyone with serious questions, has, abandoned it.

The site is now just riddled with the lowest possible quality questions.

If you're an SO user, and you're concerned about the "future of SO", I encourage you to just click on that link to, well, see the "future of SO" (as sad as that sounds).

Even if you're not a game engine programmer, or involved in software, just click on the link, and click "newest questions" to see the recent flow. Again even if you not a software engineer, you will immediately perceive the really, really notably low, remarkably low, quality of the fluffflood of questions.

For a few years there, many mods would scream "Just delete bad and duplicate questions"...

but nobody did it.

(And then ... who knows if it would make any difference if mods had done so?)

You can see literally years of discussion on it here,

http://answers.unity3d.com/questions/432710/meta-unity-answers-is-degrading-.html

and many other meta discussions there: long-time top mods just giving up, etc etc.

Indeed, if you bother to read through or glance through some of that material, it is a case study of a forum going to the dogs.

(I have no idea if this is, or is not, happening to SO, of if the "mechanisms of failure" are the same. I offer it as a fascinating reference point; an example of a once popular and excellent QA site which has gone to hell.)

Notice on that site ...... sundry proposals made by desperate keen users, as the site was slowly going to hell.

Notice proposals of every variety ...... technical, social, etc ..beginners sections, advanced sections, moralistic rules, actual legal remedy, etc etc.

(It's actually really - you could use the words "quite sad" - to see the decay from vibrant members desperately suggesting something, to, eventually, people saying (I quote) "fuck this" and leaving, to eventually people simply not showing up.)

Fascinating tidbit:

If I'm not mistaken, due to the insane popularity of Unity3D, that site is (I'd guess) the largest example of "A QA forum gone to hell."

Notice the overwhelmed Unity staff members (who consistently tried to do the best job possible before the Fall) - it's possible, people here on SO probing in to the whole issue, may wish to ask them questions, or whatever.

It's worth noting that the Unity site "is now dead, functionally" means: hence, if I post a serious advanced question, quite simply, nobody sees it. The flood of "ridiculously low quality" questions is overwhelming. So the site is not usable, not functioning, you can not get "answers" there.

(It costs something like US$2000 a year to be a professional Unity user; as a curiosity, it's actually commercially significant that the forum is now deadfluff.)

An interesting phenomenon: (I don't know if there's some equivalent here on SO). For awhile at the beginning of "the fall". More serious users would sort of PM each other "there's an interesting question here" regarding worthwhile questions. However I'd say this has just been abandoned; most people have given up and the fluffflow is just totally overwhelming.

Note that Unity3D, as a topic, in inherently "dangerous territory for fluffflow." The whole idea of Unity3D (if you're not a software engineer) is that it makes the very difficult, quite easy. Amazingly, you get brand-new programmers trying to learn programming, I mean from day 1, with a 3D rendering physics game engine ("!!"), which is kind of a recipe for disaster in terms of the QA site aspect. So, that issue tends to make the "answers.unity3d collapse" more of an extreme example; perhaps you don't suffer that so much on SO, I don't know.

{I think - I'm not an expert - the sort of moral equivalent on SO is "fuckers asking homework questions". As far as I can see on SO, those of you who "actually care", a pretty annoying issue is the FHAHQ issue. I guess a similar thing on answers.unity3d was "absolute beginner programming questions unrelated to Unity as such." Anyway, it might help with the thinking here.}

My personal takeaway from the whole affair?

Social solutions will not work.

Sad but true. If someone on the meta discussion realises "Hey, we mods must _ _ _ to solve the problem!"

The simple reality is: it Will Not Happen.

The ONLY solutions are technical solutions. i.e., all new questions are simply plain deleted after 2 hours unless 4 of 20 top-ranking mods certifies the question is original and worthy ..... or whatever.

Social solutions do Not Work. Proof, click to the Unity site.

{But see my caveat below. It is simply factually the case that SO, like say any Western Government, is now an I.S.M.O. ..... an Incredibly Slow Moving Organisation. It's inconceivable that anything Radical (say - "eliminate membership," "make all pages bright pink," or whatever) will be tried. You might as well suggest a Western Democracy would try fast, aggressive solutions. So, the issue is settled. Click to the unity site to see SO's future.}

And here's a contrary example, with an equally bad outcome!...

Consider Parse.com, which is becoming wildly important in many aspects of mobile computing. They have their own QA forum. Now, the owners TIGHTLY CONTROL the forum, so there is NO crap content.

Result ... nobody likes or uses the forum. :/

It's tough ...

And for a complete scientific analysis, with diagram...

Amazingly, this question actually totally explains the dynamic, which ruined the above two sites:

https://meta.stackoverflow.com/a/252077/294884

Regarding SO being ruined in the same way, you can simply place bets on when it happens. There is - absolutely - no cure.

(SO could aggressively try different strategies, to at least try to find a cure. Nobody knows what the cure is: you can trivially write down a list of aggressive ideas which could be aggressively actually tried. For example, it might be that you simply must vote on a post if you are even an unregistered visitor, it might be that "registration and membership" has to be completely eliminated form the SO concept, it might be that only the 3 highest ranking members on the whole site can vote on posts, it might be that ALL posts are automatically eliminated after 36 hours unless a high ranking member approves them, it might be that you simply can't have a ranking unless you use an RSS tool to constantly monitor posts, it might be that you must eliminate 10 weak posts a day to have a score over 5k -- etc etc -- it's easy to think of aggressive ideas. But - simple fact - SO is now an incredibly slow moving organisation; nothing like this is going to be tried. It's just that simple. [There would be a huge bizarre panic by owners and 'constituents' at any aggressive ideas, like eliminating posts, blocking users, adding an "advanced" section or whatever.] It's simply a fantasy to believe anything aggressive will be tried -- you might as well hope for a modern Western democracy to try radical aggressive ideas on problems. So it's not going to happen. You can count the days until SO meets the same fate as the above two examples.)