The Nano has some nice features - I'm guessing that its somewhat unique encryption extensions might be quite useful in a lot of web-based applications.

I wonder how a rack of these compares to something like Niagara (each core is slow but it has many cores).

This sounds like a good low power custom Linux server platform.

(Beauty) x (Brains) = Constant
With a few exceptions, this law holds good. It also applies to this article.

As James points out, each VX8 server module has a TDP of 30W - not the entire chassis.

Also, $400 is the price per module - not for a fully loaded chassis.

The Nano processors are being used because they're low power and virtualisation capable, so that server management gains the advantages of hardware independence and capacity changes on demand.

The 2U chassis features 12 servers, with EACH server consuming 15-30W. Not 30W in total for all servers running as implied in your article.

"Next week, Dell plans to reveal a rather original system design that places 12 full servers running on Via’s Nano chip in a 3.5-inch-high case. That’s three times as many servers as Dell usually squeezes into similar, compact systems. Equally important, each server will consume 15 watts to 30 watts, or about one-tenth the power of a standard server."