A few months ago, I exposed myself as a digital cretin based on how often I violated one or more of the apparently well-known email etiquette rules. It probably won’t shock you to learn that I’m still doing things wrong—and you just might be too. Before you say, “OK,” though, keep reading please.
It turns out the worst response you can give to an email that’s asking you or telling you to do something is “OK,” at least according to internet linguist—who knew that’s a job?—and author Gretchen McCulloch.
Here’s more from a Mental Floss post on email etiquette (side note: I just learned this is also called “netiquette rules”):
That’s because short replies can come off as flippant or passive-aggressive, she explains. The word itself isn’t necessarily rude, but the brevity can be problematic. It’s far safer to tack another word onto your reply, like “OK, great” or “OK, sounds good.” You can throw in an exclamation point to show enthusiasm, but by all means, avoid the dreaded “k.”
As a general rule, McCulloch states, “Anything that’s shorter can sound curter. Anything that’s longer can sound more polite.” Oddly enough, even “kk” is preferable to “OK” in McCulloch’s eyes because it softens the delivery, in much the same way that “bye-bye” sounds nicer than “bye.” This word repetition even has a name for it in linguistics: reduplication.
Of course, there are exceptions, and your correspondence may vary depending on who you are emailing. If your boss or client uses “OK,” then it’s probably fine for you to use it, too.
This technique, called mirroring, is usually a safe bet. “Generally what I try to do in emails is mirror what the other person is doing,” McCulloch says. “If I see someone else saying things like “ok cool,” I can do something in that family.”
How many of you are struggling to keep up with the netiquette rules and possibly unintentionally insulting or alienating the recipient? Words matter, so make sure to choose yours carefully.