A piece of punctuation older than the printing press has become an accusation.
Put a long dash in a sentence, the one wider than a hyphen, and somebody will announce that a robot wrote it. Five centuries of quiet, elegant service in English prose, and now it testifies against everybody who uses it.
I should declare an interest immediately. We run a standing ban on it across everything we publish, including this. So read the rest knowing I have already picked a side.
Why the machines fell in love with it
Because it is the most useful piece of punctuation in the language for a writer who is not entirely sure where the sentence is going.
It joins two thoughts without committing to how they relate. A colon promises explanation. A semicolon claims balance. A full stop ends things. The long dash does none of that, it simply gestures onward. If your job is to produce fluent text at speed without a firm position, it is the perfect tool.
People write that way too, and always have. The problem is not the punctuation. The problem is that the machines used it at a rate that made it a signal.
The rest of the lineup
It is not travelling alone, and the others are worse because most people cannot name them.
"It's not just X, it's Y." "In today's ever-evolving landscape." "Let's dive in." Three items in every list, always three, always rising in importance. An opening line that restates the question you asked. A closing paragraph that summarises a piece nobody has forgotten because it was four hundred words long.
And the tone. Relentlessly positive, entirely frictionless, faintly enthusiastic about everything, committed to nothing.
Why this matters to somebody with a licence
Here is the practical version, and it is not about style.
Your listing descriptions and your market updates are the most-read writing you will ever produce. If they carry the tells, a growing number of readers will conclude nobody was home when it was written. That is a small trust cost per reader, applied to every reader, forever.
Worse, the same generator producing the tells is the one that will cheerfully write "great for families" or "safe neighbourhood" into your listing copy, because it learned from decades of listing text written before anybody was careful. The tells are cosmetic. What travels with them is not.
So the punctuation is a proxy for a real question: did anybody read this before it went out with your licence number under it?
In defence of the dash
I want to be fair to it, because I have banned it and that is a bit rich.
It did nothing wrong. It is genuinely the most flexible mark available and some of the best sentences in English depend on it. Punishing a punctuation mark for the company it keeps is silly, and in five years this will read like a period detail.
We banned it anyway, for an entirely unglamorous reason: readers currently treat it as evidence, and I would rather remove the evidence than argue with the jury. That is not a principle. It is a preference, and I try to know the difference.
What I would actually do
Not a style guide. Two habits.
Read it out loud before it goes out. Every tell in the lineup is audible. You will hear the rising-three-item list and the frictionless enthusiasm long before you spot the punctuation.
Put one specific, checkable thing in every piece. A street. A number. Something that happened on Tuesday. Generated text is fluent and unspecific by nature, so specificity is both the cure and the proof.
Any road up
Nobody has ever chosen an agent because of their punctuation. Plenty of people have quietly decided somebody was not paying attention.
The dash is innocent. Use it or do not. Just make sure a person read the thing before it went out with your name on it.