OK, so they use "zones" (beefed up multi-user, which should have less overhead than virtualization) and a fork of OpenSolaris (interesting features, reputed to be very stable).
I wish they'd just say that, as it makes their "Faster than VM" claim seem a lot less wild.
Shared hosting is actually more efficient than VMs, but it got a bad rap due to massively oversold hosts.
Sun engineered some amazing stuff but eventually got bought out by a company with weaker engineers but much, much stronger sales team. After being burned in this way I could see how a bunch of former Sun staffers might use their former technology but call someone else in and say 'look, we can't market for shit - you have a go'.
And that's my guess on why their marketing spiel might seem a little vague to a tech person.
I wish they'd just say that, as it makes their "Faster than VM" claim seem a lot less wild.
Shared hosting is actually more efficient than VMs, but it got a bad rap due to massively oversold hosts.