What's the difference between a RAID enclosure and a NAS?

Question

I was taking a look at NAS's and RAID enclosures and was curious as to the difference between the two. Both seem to hold your hard drives. Both seem to provide hardware level RAID. Is there a major difference between the two?

NAS http://www.newegg.com/Product/Product.aspx?Item=N82E16822122044

RAID enclosure http://www.newegg.com/Product/Product.aspx?Item=N82E16816401148

Solution

NAS connects via the "network" , and can be made available to many computers via the network. a "normal" raid enclosure connects via some available port or card installed on the computer, and is much more like an "internal" drive in an external box.

A normal raid can still be available via the network, but through the computer, which would tax the resources of the computer it is on.

A person would be more likely to chose a Nas if they were thrilled with network connecting, and wanted it to be similarly available to all devices on the network.

A person would be more likly to chose a normal raid box if they were on a single computer and wanted the most speed, and least slowdown of thier network connections for other accesses. Plus depending on many other factors the direct connected storage could be more secure.