Is this spam or a legitimate inquiry?
Anyway, if legitimate I find it interesting that one of the key technologies behind their grid is that they NFS mount user directories to their web servers and load balance these servers using a (network) load balancer.
Sound a little like what DreamHost does? Sure it does. The key difference is that DreamHost doesn't load balance the CPU load across machines. But then again, theory says that if you're running all low load sites, your server performance won't be affected by high load sites on your server because... there aren't any. By high load sites I mean sites that utilize a significant portion of the CPU for extended periods of time.
I'd also worry a bit about the GPU limit and automated overage billing, but that's without any personal experience with typical sites.
Caveat: My experience with clustering is with large enterprise applications where one site requires 10's or hundreds of dedicated servers. We had to significantly re-engineer our apps to run in a clustered environment (though I admit that you wouldn't have to if you were running Apache and PHP in CGI mode - the implied statelessness suffices).
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