I was always taught that overuse of the em-dash is poor style. Oftentimes using more specific punctuation (comma, semicolon, colon, parentheses) more clearly communicates the structure of a thought. Em-dashes are a lot more freeform and informal. They communicate a similar tone as when you're speaking and you suddenly stop to mention something that just occurred to you.
In this sense, the idea that "em-dash = AI" has become something of a strawman. The mere presence of em-dashes isn't what indicates AI, it's the fact that LLMs use them so frequently, and use them for formal structure (where another punctuation mark would work better) rather than informal breaking up of related thoughts.
> it's the fact that LLMs use them so frequently
That's the problem with all the LLM writing tropes, really. When used correctly, they are all helpful writing tools to get your point to the reader. The em-dash, "it's not X, it's Y", "Not X, Not Y, Just Z", "It's worth noting" (I use that one a lot in my own writing), etc.
It's not that the patterns are bad (they aren't), they are just over used.
> "it's not X, it's Y", "Not X, Not Y, Just Z"
Interesting how LLMs have their own preferences too. Those in particular are very often used by ChatGPT, while Claude until recently couldn't stop saying "You're absolutely right!"
I also have a problem now with "it's worth noting", I use it a lot, I still like it, but now it's a dangerous phrase because of LLM associations.
> Em-dashes are a lot more freeform and informal. They communicate a similar tone as when you're speaking and you suddenly stop to mention something that just occurred to you.
Isn't that supposed to be en-dash? I swear I remember em-dash being more restricted in use.
No, an en-dash is used for a range, like "5–10", or in talking about two things and their relationship, like Franco–Prussian War.