Earlier quoted context omitted.
> Quick question I'm always wondering why people prefix a question with the statement "quick question". Now is my chance to ask. Is the question typed quickly? Should I imagine you speaking it in a quick manner? Is it meant as "off topic question"? Do you expect an answer quickly? What does it mean when you prefix your question with the words "quick question"?
It means that the asker believes the question is relatively short and thus won't be too much of a burden on the askee.
For example, when PM May had finished presenting her new manifesto before the election one might ask "Quick question: how are you going to pay for all that?" to highlight the fact that no costings had been included and suggest you thought it was unrealistic (or hiding tax rises, or whatever).
"Quick question" is used genuinely too. One use appears to be "don't go too deep, give me a superficial answer".