People say Google is Search Engine Gaint, but it is half true. Google is the Super-duper statistical company. The way the crawl and store the data and serve the accuracy result (Most of the time) demonstrates their statistical capabilities. Three years back, the consistencies across datacenters are not so great.
But now, If a webpage content crawled and Google, the data has been sync 99.99% across datacenters. This is really awesome.
Search with below Google datacenters and see the results. Experience the consistency