Em dashes are to AIR MAIL what Vesper martinis are to James Bond—our signature. So you can only imagine how our editors were feeling—shaken and stirred, that is—when they learned their punctuation mark of choice has not only been bastardized by villainous L.L.M.’s like ChatGPT and Claude but had also become a “GPT-ism,” or an obvious tell for machine-generated text.
The em dash comes with a very particular set of rules: it can function like a comma, a colon, or a parenthesis, but never like a hyphen, which joins separate words to create a compound. Brits leave a space on either side of an em dash, while Americans—who love to change British rules—don’t.
