I don't agree that one should "write like they talk." Certain forms of writing are fundamentally a higher and more complex register of language, because they have gone through more rounds of refinement and editing, while speech is generally composed one-shot; you can't "go backwards" and make edits to your speech, except by going forwards and issuing more speech to make corrections and amendments to what you've already said. That is, speech is "write once," given the fact that it needs to be composed extemporaneously.

Try talking like an academic on the street - you'll get laughed out of the alleyway. Informal conversation often needs to target the lowest common denominator, which is the most you can expect from the average person out in the "real world;" that is, of course, unless you are reading from a prepared speech - which is the composition of a speechwriter, prepared ahead of time, instead of improvised on the spot. Writing can target more advanced audiences because you're not limited by space and time to the people in your immediate vicinity, but people who self-select into your subject matter - for instance, on fora like this one, which represent a small minority of technically inclined readers.

One can write extemporaneously in this style - that's the IRC and chatroom register of written speech, and it has its place, but I don't think this is the form of writing that the author of the article had in mind. For instance, I doubt that this article was composed one-shot in an IRC chatroom and then published verbatim, but went through many rounds of editing. That's not how "people really talk."

Of course, if one is in more enlightened company, their informal, extemporaneous speech can start to take on more complexity and jargon. You need to target your communication to your audience.

For what it's worth, most of this post was written one-shot with minimal revision, but with pauses to think about what to write next. These kinds of pauses are usually known as "awkward" in every day speech over beers. I will maybe go over the post and make some edits as I read over it again.