TL;DR belongs at the top of an article

 TL;DR

• if you are writing an article and plan to add a TL;DR section, then put it at the very top, right after the title.
• that's it, no excuses, end of discussion.

It has happen to probably everyone to read an article, reach the end of it only to see a TL;DR section right at the bottom, and thinking: "eeh i wish this would have been at the top so i didnt have to read (DR) this long article (TL) to gather its core ideas".

If the reason for "Too Long; Didn't Read" to exist is to avoid the reader to go thru the whole article to get its main points, then the natural place to present it is at the very top of said article.

So if you're planning on writing something and to add a TL;DR section (you don't have to, of course, but if you do that work too) then please position it at the very beginning of your work.