Introducing Google Container Engine (GKE) Node Pools

The blog post didn't touch on it in detail, but this allows a single Kubernetes cluster to span multiple zones.

Super highly requested feature - lets you run in multiple zones or with multiple machine types (high mem, high CPU).

what's the difference between multiple clusters in account and multiple node-pools in cluster?

I guess pods still may migrate/replicate between nodes in different node-pools, but can't between nodes in different clusters.

Anything else?

Yep - that's basically the big difference. Also, they are separate Kubernetes masters, which can provide additional high availability.