If you even looked at this article you'd know..
It's a data box (essentially) which can connect to your LAN network via ethernet and/or esata data cable to a computer (which your computer could share over a network as well). However, the whole point of NAS equipment is to have access to the drives over a wireless network so certain types of equipment such as tablet computers and/or set-top boxes for home theater systems can stream, store and poll video/audio data from them.
Imagine having the contents of blockbuster in this box with 4 x 3tb hard drives.. 12tb of standard definition video data. Of course it only comes iwth 4 x 500gb drives but I bet it's upgradeable. Plextor wouldn't be that stupid to design a box w/o being able to upgrade the drives to at least 3tb each.