(I am the OP - but note that I do not consider there to be any "drama" here).
My comment on meta was not clear, I believe - perhaps also my question (although in that case, an edit would be most appropriate, really). Before I give my answer to the overall question, here's the explanation of the "Time War" question.
The Wikipedia page about the "Time War" is (unsurprisingly) encyclopedic; it's long (much longer than even good SO/SE answers), and covers in detail not just how this story was introduced into the Doctor Who universe, but the entire plot of the substory, discussion of continuity, and so forth.
What I wanted was a detailed, interesting, answer as to the origin (specifically the introduction into the universe, not the entire backstory).
If you consider that Wikipedia is an authoritative source that contains all relevant information (it appears some people do, which is sad but off-topic) then you could indeed answer this question using only information within that Wikipedia page. However, IMO a good answer would do more than just summarise particular sections of that page, and it would be specific to the question (in the same way that SO answers are specific to the question, and not 'here's a link to a page that explains all about binary search trees).
My comment about spoilers was referencing the fact that the Wikipedia entry contains far too much information, that is not answering this specific question. I obviously have no problem with answers that are full and detailed and on topic to the question.
In terms of the larger question: "spoiler" is a vague and subjective term. There are elements of story lines that are clearly going to have a significant impact, but there are many others that would "spoil" the story for some and not others. For example:
(Warning: Star Wars related)
Darth Vader is Luke and Leia's father.
I think this clearly falls into the former camp.
(Warning: Serenity related)
This is much more subjective.
(Warning: Star Trek related)
Data ends up captain of the Enterprise.
This would probably not be considered something that "spoils" watching ST by most (especially you consider how it eventually occurs).
IMO good answers should make judicious use of the spoiler tag. If there's something that the answerer feels would spoil the story but is necessary to make the answer interesting and detailed (i.e. good), then include it in the answer but make it as a spoiler. If the answerer doesn't feel it's a spoiler but the asker does, then that's the asker's fault for not being clearer.
I'll go and research my question and answer it myself with the sort of answer I hoped to get, which perhaps will demonstrate this more clearly. (Pre-emptive note: the fact that I answered my own question does not mean that it was one that I should not have asked. It took a lot of work to find out what I did and summarise it - work that I believe that someone more expert in Doctor Who than I would not have needed to do. There are also parts of my answer that I am not 100% confident in, that the expert could probably have done better).