Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications.
In the official site of Kubernetes it says "Google runs billions of containers a week", my question is: if a container here means a containerized application, does that mean Google have billions of applications? It simply sounds ridiculous, what am I misunderstanding?
Containers are great because they can scale out a single process across multiple physical/virtual host machines.
Google merely scales out their applications (Google.com, Gmail, Google+) across a large amount of hosts by using Borg (which was the inspiration for Kubernetes) and the container methodology.
Gmail itself can be millions of containers (just throwing out a number). It need not mean that many applications. There might also be short term jobs etc.