> - dash: compounds word-parts (Sarbanes-Oxley)

That's a hyphen, and (to be pedantic) style guides usually do not consider it a dash.

There's also the 2-em dash in some style guides for redacting words, and since care needs to be taken to avoid a line wrap between the em dashes, Unicode has a character for it: ⸺

Finally,

> - em dash: adjoining thought (Hey, so — <declaration>)

This use is sometimes discouraged by style guides, and in many cases, it can be replaced with a colon, comma, or semicolon.

In general, even before AI, the em dash is often considered overused.[0] My guess is that the em dash is perceived as sounding educated, so novice writers who learn about it end up using it recklessly, and LLMs could've picked up this habit from them.

[0]: https://slate.com/human-interest/2011/05/em-dashes-why-write...

Fun fact! Where a compound term is formed by joining two nouns of equal importance — such as Sarbanes–Oxley or attorney–client privilege — an en-dash, not a hyphen, should be used.

Furthermore, the conventions for the first (parenthetical) use case, as far as I understand, are either em-dash without spaces (Anglosphere convention), or en-dash with adjoining spaces (Continental convention: German, French, etc.), but rarely em-dash with spaces (as in the article).

> 5.2.1 Use spaced en dashes – rather than em dashes or hyphens – to set off phrases."

– Robert Bringhurst, The Elements of Typographic Style

My favorite is the Chad Wittgenstein usage. — Where you add an em-dash after periods to slow down the reader. —— Sometimes a double em-dash to keep your reader on their toes.

With HTML, I can do everything as a <div> and the eyeball reader doesn't know/care. Where it matters is that I'm stripping semantic meaning, which hurts computers and possible accessibility devices.

Most of my life, the same has been true about dashes. I use - for every one of the kinds you provided because - lives on my keyboard.

Is there real value in caring? Does it have the same semantic—stripping effect for computers/accessibility devices? The part of me wondering if I really should care is trying to suss out if this is a real problem or just an argument for semantics pedantics.

Not to forget the chōonpu ー to mark elongated vowels in Japanese.

Konnichiwaー

I just know that MS-Word will replace a hyphen with an em dash in practical use, which is a big part of why I didn't really pick it out as an AI thing in general. Though AI, in particular Chat GPT, does tend to use a lot of them.

I’m surprised to see that you put spaces around the em dash in your example.

Sounds like you'll appreciate my favorite related bit of typographic dash pedantry, from https://www.merriam-webster.com/grammar/em-dash-en-dash-how-...

If you want to be official about things, use the en dash to replace a hyphen in compound adjectives when at least one of the elements is a two-word compound.

    the pre–Websterburg Bakery era

n.b. I don't know how to code an endash here. Would love to learn!

I still don't see the actual point, as the meaning of the dash is already clear from the context around them. The em dash is surrounded by spaces, the en dash is surrounded by numbers, and the hyphen is used in compound words. A single character, the one that already exists on my keyboard, works fine for all three.

Which one is the minus symbol?

In many countries around the world, em dashes also express dialogue!

I grew up reading novels and plays

Inspector Lestrade and Holmes were speaking:

— What’s up?

— Not much

— Cool.

em dash is awesome. I immediately know I am talking to a bot.

which one of those is a hyphen?