It's best to think of this as a different kind of new RAID array (even though it's not RAID). Before this developer's tests, it wasn't completely clear how Apple was implementing the Fusion Drive, and whether it was partially hardware-based. It's still not 100% clear, but it's now looking like it's software-based and can work with any 2 drives, just like RAID. In the past, Apple offered RAID as a build-to-order option for some models, just as they're now offering Fusion Drive as an option, but it's effectively just saying "Do you want us to include 2 drives and set them up as a 'Fusion Drive'?"
All that said, this article is not meant for the average Joe ordering a new Mac from Apple. To them, it will be just one drive, a Fusion Drive. Apple's term is a marketing term for them, it's not a "tech name". This article is meant for us tech nerds who are either interested in how it works or like rolling our own unsupported solutions. The interesting thing will be whether Apple exposes this to everyone in disk utility and makes it easy to set up a Fusion Drive on other Macs.