Comment by dragonwriter
1 hour ago
> No space em dash = a real person who has been bulldozed by LLMs using it with spaces.
Setting an em-dash used for parentheticals closed (with no space)—or sometimes with thin spaces—is the common American literary/academic style (Chicago Manual, APA, and MLA all prefer closed); setting it open—with full word spaces—is the common American practice in journalism (reflected in the AP style guide). Not using em-dash at all for that use, but instead using an en-dash set open is the common British practice.
And that's why it should be interpreted as a one way signal. I.e. lack of spaces is a great indication a human wrote it but spaces sround an em dash alone is not a particularly strong indication it was AI.
Even for Americans, there are several style guidelines/modern preferences (particularly around web content) which don't guarantee the lack of spaces around an em dash. Hence even American LLMs using spaces. Ecen my natural em dash usage always included spaces as an American.