[SOTGO]

There's enough places where em-dashes are inconvenient to type that I find it to be a reasonable indicator, particularly on the web. I don't think most people know how to generate an em-dash with a hotkey, so if I see one in a Reddit comment for example there's a high likelihood that the comment was either LLM generated or at least copy-pasted from somewhere else. Generally speaking in the past I observed a low prevalence of em-dashes on the internet except in more formal writing, so if I see an em-dash in a context where I ordinarily wouldn't expect one I do get suspicious. It's the same thing with the green check emoji, it's possible that a regular user typed it, but pre-LLM I can't recall ever seeing them, so these days I automatically assume it's AI generated content