We announced with Intel back in November that we would be getting early access to Skylake [1]. Today's announcement is that we're ready to let more people in the door.
E3 is not a server SKU, it's meant for workstations and it's more similar to i7 than E5. It lacks various features including ECC RAM which, I suppose, is a no-starter for cloud hosting. Also some virtualization capabilities are missing, notably accelerated interrupt injection (APICv+posted interrupts).
Skylake Xeon E3 is on the current older server chipsets..
Purley is supposed to be a significant improvement.