An IP address that is used by multiple devices in multiple locations. Routing determines the “nearest” device to which to route any datagram based on geographic/availability considerations.
Simplifies DNS setup by only requiring a single IP for a complete distributed application.
GCP uses those for the Global HTTP load balancer
AppEngine: a PaaS GCP service focused on simplicity of web backend development. Compare Firebase
Autoscaling: GCE ability to add or remove VM instances depending on the load sustained by an app, and balance traffic between them