Google datacenters are different copies of the Google search engine index that are located in various geographical locations of the United States and the globe.

Do NOT be Fooled by Datacenters

Datacenters are used for Internet access load balancing. You will probably get connected to the datacenters that are geographically closest to your Internet Service Provider.

Datacenters and the variability between how your pages rank differently on each of the different Google datacenters confuses the heck out of most people.

It is not a Gremlin playing with your site, but rather just a ripple in the updating of hundreds of different Google datacenters.