I see a few people making the expected "It's just four motherboards wired together with Gig E"-comments. While I won't object to that, I'd say this is not about a groundbreaking evolution in hardware, more a case of demonstrating what's possible today with COTS parts. Adding to that the compact packaging, and the ability to run off of a single power cord, it's a nice setup IMHO.
While it does not have the interconnect of "true HPC" hardware (a bit of a fleeting distinction, but bear with me) it'll surely be suitable for a lot of the simpler, yet still compute-intensive tasks out there ("simple" here meaning not needing a lot of intra-node communication).
On the flip side, it might fuel the "hell, I'll just build my own cluster"-mentality going around these days. I work in the HPC group at a university, running linux clusters, IBM "big iron" and a couple of small, old SGI installation, and we certainly see a bit of that going around. Problem is, sure, the hardware is cheap and affordable, but getting it to run in a stable and sensible manner without spending large amounts of time just keeping the thing together is a challenge, mainly due to the immature state of clustering software. As many researchers are not exactly keen on spending time solving problems outside their specific field, they're usually better off letting somebody else administer things, so they can just log on and run their stuff.
But for individuals and small groups of people who are computer savvy enough to handle it, things like these are definately a "good thing" (TM).
