As someone who has never used Org-mode, and only very briefly dabbled in Emacs during college, I actually think that's a pretty safe assumption around these parts. No?

Even if you are uncomfortable assuming that, search results for "org-mode"/"orgmode" are unambiguous and helpful for anyone out-of-the-loop and curious, so it doesn't seem exclusionary or like a secret in-joke reserved for a secret society of HN elite.