for any Discussion-section post under /r/discussion/lw/[code]/[title], the exact same post appears at /lw/[code]/[title] (and, when viewed there, looks as if it is in Main because the “MAIN” at the top is boldfaced and the “DISCUSSION” is not);
when you get a reply to a comment on a post in the Discussion section, in your inbox the “Context” link attached to that reply goes to the “Main-ified” version.
… which is how I came to think your post was in Main rather than Discussion. Sorry about that.
Hmm, so you did. It turns out that
for any Discussion-section post under /r/discussion/lw/[code]/[title], the exact same post appears at /lw/[code]/[title] (and, when viewed there, looks as if it is in Main because the “MAIN” at the top is boldfaced and the “DISCUSSION” is not);
when you get a reply to a comment on a post in the Discussion section, in your inbox the “Context” link attached to that reply goes to the “Main-ified” version.
… which is how I came to think your post was in Main rather than Discussion. Sorry about that.