Interesting work.
Of course, the response will be “It’s just micro-evolution.”
I ask this not to be argumentative nor because I seek to make a point, but because of my ignorance in this area (which is profound).
How is this an example of macro, and not micro, evolution?
It’s not. It’s an example of evolution in action, and the demonstrable reality and efficacy of natural selection acting on random mutations at eliciting adaptive change in the genetic and phenotypic makeup in a population of organisms.
It’s not claimed to be an example of macroevolution.
Ok…gotcha. Kinda. I just thought from your comment that you meant that it was something other.
Remember, when you’re talking science to theologians talk slow and simple. You wouldn’t want me to get all “genus maeistaticum” on you, right? 
Thanks for the clarification!
The reason @nwrickert said that would be the response is that’s how creationists commonly dismiss examples of evolution in real time. The implication is that sure, there’s microevolution, but it doesn’t add up over time to produce big changes, and there’s no such thing as macroevolution. They fail to notice that the evidence for macroevolution lies elsewhere.
I should add that many of the creationists who say they accept that there is such a thing as microevolution also, for some reason, argue against both almost every case of it published and the very idea of natural selection, drift, random mutations, and so on.
Yes, it is micro-evolution. Already, @John_Harshman has given a good explanation of why I made that earlier comment.
Ed Yong is a fantastic author - loved this story! Amazing to see the results of this ambitious experiment.
But, you are exactly right. As important as it is to the overall observation of evolution, it will be dismissed by many non-scientists.
This experiment has already been done by nature. In the U.S. southwest there are a species of mice called rock pocket mice. They exist in two colors - a dark coat variety lives on dark volcanic rock, a light coat variety lives on sandy colored soil.
What makes this experiment neat is the researchers can see the selection effects in near real time, every generation. 
This paper is from Hopi Hoekstra’s group at Harvard, and they’re the same people who’ve done a lot of the work on those “rock pocket mice”, characterising the genetics of the adaptation etc.
YESSSS
Would it at all surprise you to find out that the term “random mutation” does not appear in the article?
It doesn’t have to.