This question, and its answer, are pure gold. It's highly-informative; it speaks to an issue that is of intense interest to web developers; it addresses a topic area that has a shortage of good, actionable information; and it has a comprehensive, incredibly useful answer.
There's really nothing bad I can say about this post, except for one thing.
It is technically off-topic.
Because of its prominence, it is regularly used to justify asking other Big-List questions, like https://softwareengineering.stackexchange.com/questions/320302 It is also cited when justifying other questions that are clearly Too Broad. I can't cite the exact conversation now because a moderator on Programmers deleted it, but it went something like this:
Your justification for Too Broad reminds me of the "Too Localized" debacle. When you get the "Too Broad" reason as wrong as you did on "What technical details should a programmer of a web application consider before making the site public," I don't put much stock in anything you say about "Too Broad" anymore.
My response was something along the lines of
I've been a moderator on Stack Overflow for several years now, and have seen every possible way that these sites can be abused. Believe me, if I thought there were a way to better support these questions, I would be the first to wave the banner.
And I do believe that.
So I pose the question: how can we better support these kinds of posts?