This is not Seagate's first foray into consumer NAS products. The DockStar (see Pogoplug and DockStar Are Internet NAS Boxes) is an Ethernet-based solution. The USB hard drive is removable but even on the road a use has to plug it into a USB socket. At home, or in the office, the NAS base can be connected to a network with wireless support.
Seagate is targeting tablets like Apple's iPad (see The iPad Initiates The Tablet Tsunami). The iPad lacks expandable storage and it does not provide a massive amount of on-board flash. It does have wireless support and streaming videos over the air is a common occurance. This makes it an ideal mate for the GoFlex Satellite.
The GoFlex Satellite will work with any wireless-enabled device from netbooks to laptops in the future. For now, there is an iPad app that is required to access data on the device. This sort of puts it in a different category than a true NAS box that provides standard network access using protocols like CIFS, AppleTalk and NFS. In a sense, the link is more like a Bluetooth pairing or a dedicated external hard drive with a wireless connection. Hopefully the GoFlex Satellite will have an option for true NAS operation or someone can hack it to run Linux.
It is not the first NAS box with wireless support. There are plenty of wired NAS boxes with built-in WiFi. They are just not as portable as the GoFlex Satellite.
Like the iPad 2, the GoFlex Satellite is a natural progression based on the latest available technology. Low power hard drives, low power WiFi and a 5 hour battery make the Seagate unit possible. Likewise, the USB 3.0 features (see USB 3.0: A Tale Of Two Buses) blend well with the product. USB 3.0 provides more power for charging as well as the highest avaiable bandwidth. The latter is key to uploading movies to the drive assuming you can get them or have a way to rip them from DVD or Blu-ray disks.
A wireless NAS box can be useful for other embedded applications. It just takes a little imagination. I'll leave that up to you.
Of course, there can be a downside. It could get crowded, from a radio spectrum perspective, on planes, trains and apartments. Just try to get it to work at the Consumer Electronics Show in Las Vegas.