TL;DR's should always go on top
tagxt.com
tagxt.com
If I understand correctly, you're saying that if there is one, then there shouldn't be one? I agree that the article should be iteratively deepening, but that doesn't change where a TL;DR section should go if there is one.
If there is one, put it at the top; if not, give me all the information I need at the top and explain later.
A TL;DR is an alternative to reading the article. If I have time, I'll read the article (if the title sounds interesting). If I don't, I'll read the TL;DR, bookmark it and refer later if I think I might need more info later.
It's like the title 2.0, not a different name for an abstract.
I like the TL;dr button idea that at any time takes me there, but that seems infeasable for most of the blogging population to implement.
Screw the conventional construction of an article. TL;DR isn't a spoiler either, because most people don't write comments in a coherent linear way like a good story. It takes most people three paragraphs just to get to the meat of what they're trying to say.
If you feel you need to use a TL;DR, you are a crappy writer and/or have written an unnecessarily long-winded comment. Put the TL;DR up top. Either that, or rewrite your comment.