I'll start with this other question which sparked my thinking cap. It's becoming extremely overwhelming with the great number of new users who seem to think that Stack Overflow is a forum, that they can ask whatever they want, ignoring the FAQ and the strict guidelines we have here. It seems that anyone who has a simple question can come create a new account here, throw their entry-level question up, and expect a bunch of people to tell them exactly what they need. Unfortunately, that's of course not how these sites work.
Imagine a new user who's never used any Stack Exchange sites, and doesn't know how it works, coming to Stack Overflow for the first time. They are new to programming, and have a lot of learning to do. They create a new account, and ask their question such as "How to write a web hook with a third-party API?". Now imagine how critical people will be to them. That user will cringe and start fighting back in the comments with "Why do you have to be so mean?"
Now, imagine a new user, same as before, coming to Stack Overflow for the first time. When they go to register, first of all a page will show with a message explaining that Stack Overflow is not a forum, and doesn't work like the rest of the sites they might be used to. Make this mandatory for them to read and approve before even creating an account. Then, once they've registered, require that they go through a short but thorough step-by-step tutorial to understand how they should contribute to the site. Make sure they understand how everything works before they dive into it.
I personally work for a software company which has troubles getting our clients to understand how to use our software, and they always mis-use it. Kind of like selling someone a 747, but instead of flying it, they strap a bunch of mules to the front and sit on top with a whip. It's very huge and complex (inventory/point-of-sale) and there's a lot to know before using it. Well, Stack Overflow works in the same precise manner, and it's expected that people follow by the rules of how it was designed. So now I'm making training videos for them.
Currently, when you sign up, there is nothing that really forces you to read and accept before using the site. I signed up for an account a short while ago, and I did not face anything which really made sure I knew how the site worked before letting me in. Sure, there's a first question guide, but it's just one single step, kinda like a terms & conditions checkbox, which everyone tends to ignore anyway. This needs to be a step-by-step (not all in one page) tutorial. And a clear warning before they even create an account. It really sucks when you sign up for something all excited, then when you finally get to ask your first question, you're faced with terror. It's a lot better to tell someone the truth up front before they begin than to lure them in and once they're here we practically say "Oh, by the way, your questions probably will not be answered."
It's simple. We educate the newbies.