If there's going to be a tl;tr then it certainly should not go at the top, it should be an integral part of the construction of the article. Good newspaper articles were always written to be iteratively deepening - it didn't matter where/when you stopped, everything that followed was more details or enhancements of what you've already read.
In more conventional terms, this seems to be an argument about whether to start with a summary Abstract, or to conclude with a summary Conclusion. There are reasons for each, and sometimes you might do both. The ones at the end, as I usually read them, are intended to be recaps summarizing the main takeaway, not literally intended as a substitute for having read the post.
Summaries should go at the bottom and recap the points u made. TL;DR's, by definition, are there because the post is overwhelmingly long but I still want to hear the point, so it would make sense for them to go in a quick access location.<p>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.
I like a 'TL;DR' button which scrolls with the page on the left side and whenever I think 'PLEASE KILL ME THIS IS BORING' I can press it and it jumps to the TL;DR part.
TL;DR is for crappy writers and/or long-winded comments, which is why you see it a lot. It's merciful to the reader to put it up top.<p>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.<p>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.