[tomsmeding]

This has existed for a while already, I believe at least since Yosemite.

EDIT: Sorry, I didn't even read TFA. Wonder what they're talking about then.

[cosmotron]

The main difference is that, while you have already been able to change the menu bar and dock to a dark color scheme, the update coming in Mojave allows the window chrome to be dark too (note Finder being dark in the article).

[logiclabs]

Yes, they spent about 5 minutes hyping it up to mucho mucho applause by the crowd.

I was baffled!