At the Open Networking Summit, Google talked about their SDN (Software Defined Networking) technology, dubbed Espresso. They use the platform to route 20% of their internet traffic - a number that continues to grow since it's initial deployment two years ago.
Over the last few years, I've observed SDN move from carriers to large service providers and now enterprises. Google says it's this tech that lets them deliver near real-time responses to voice search and other services that depend on low latency.
One of the drivers behind Google's decision to use SDN was the need to build a network that could handle products and services that haven't yet been conceived. By using software to automate and orchestrate changes quickly, they are able to adapt to changing needs.
There's some interesting background and technical information on Google's Official Blog but I think the big takeaway is the need to deploy infrastructure that is adaptable.