But I'm someone who has co-workers in almost every time zone, on almost every continent, and in almost every geographic region, and I simply can't imagine using most of these examples with co-workers in, say, South Korea or Japan or Nicaragua. Like, the account manager who reaches out to me for help accessing a particular system in Seoul doesn't need my personal story about why I'm taking time off and all the fun (or, for that matter, not fun) things that I'll be doing — they need help gaining access to [system] in order to complete the job tasks that have been assigned to them. If I am not available to help them, they need to know who can, and if there just *isn't* anyone else who can perform this task, they need to know when I will be able to.
Not only did Kopelman manage to turn his out-of-office message into an epic poem of sorts, but also, he actually went through the trouble of creating a delightfully snarky, vacation-specific email address for his recipients.

Some people can try to contact you again and again if they think you might be available at some time. If your colleagues know that they are on a personal vacation, they are less likely to attempt to contact you. The details of the person who can assist the caller when you are not available.
I guess my first instinct might be thinking it’s rude but having seen it a few times I do get it. It really makes sense for people who get dozens or hundreds of emails a day and are gone for extended periods of time. It’s more courteous to be up front about it than silently delete like some people said they do (though I get they maybe just didn’t realize they’d need to do that).