It’s a network attached storage with some FTP/SAMBA etc managed by you via a web interface.
Think VPS with lots of storage, but with file-storage software pre-installed and configured and only ability to change users. I don’t know how else to explain.
Is it a "box" in the sense that you get your own dedicated virtual machine with some software pre-installed?
Do you get a quota on a public service ?
I'm interested but I'm not sure how is that supposed to work.