just because it's "designed to" store yottabytes does not mean that it actually does right now. they're just designing the system for the future.
That said the Wired article just cites a DoD report which say their goal was to have Global Information Grid handle yottabytes when Utah was up and running.
Except you'd probably be wrong. Your filesystem almost certainly can't handle that much space. ext4 maxes out at 1 Exabyte. NTFS might barely make it if you use GPT and oversized sectors and don't run into any unforeseen problems.