More old people and language, kinda: Punctuation edition

Usually, the least interesting aspect of language for linguists is spelling and punctuation may be at the bottom of even that category. But there are occasional exceptions. I don't know how old it is, but I've only recently (like within a year or two, maybe somewhat longer) noticed the use of periods after each word in a phrase to indicate intonation of real emphasis, where each word is being pronounced very independently of others. The classic example is probably this:

Oh. My. God.

I think of that as really informal, what you see on fb or in texts, but not in journalism. But lo and behold, TPM uses it to transcribe the speech of none other than Sheriff Joe Arpaio, in a piece written by Nick Martin:

Sheriff Joe Arpaio looked out at a wall of television cameras and started to raise his voice. The rant that followed was confused, rambling and aimed directly at President Obama.

“Show. Us. The. Microfilm,” he demanded. “I said it a while back. Show. Us. The. Microfilm. And we’ll all go back home and forget this! Where is the microfilm? Where is the microfilm? Is it in Hawaii? The Department of Health? What’s the big secret?”

Even for a notoriously eccentric Arizona politician like Arpaio, the spectacle he created on Tuesday at a news conference in Phoenix was on a whole other level.

It's really effective here, and does some work, especially in contrasting to the later repetitions, presumably said more fluently. And it's even in the headline (see the screenshot from TPM).

But is this being used so widely? Clearly the style of the article is very informal — I quoted as far as I did to get in 'a whole other level'.