just google it. it's a NETGear brand, hot-swappable, 4-bay (4 disk drives), Network Attached Storage (NAS), RAID (Redundent Array of Inexpensive Disks) server.
$1000 more or less will net you a nearly idiot-proof 5 terrabytes of redundent storage on your network with gigabit speed throughput. attach that with the right high speed network cable to your existing netgear WNDR3700 which also supports gigabit connections and you'll have a nice 300mbps storage solution.
I've already maxed out my DLink DNS-323, 500 GB 2-drive RAID box.
a cool feature of this type of appliance is it can stay attached 24/7 to the internet serving as your personal cloud server without some faceless organization having access to your personal shit.