I did this years ago so it might be different now, but I blocked google.com and some subdomains at the firewall, found a document hosted on google docs (google.com domain) link in google.co.uk search result, clicked it and instead of the link failing due to it being blocked at the firewall, a google.se (swedish) server started sending the ip traffic for the blocked document to come down. I never tried blocking google.se and then repeating to see what other google domain would send the document next, but its clear Google have written their own routing to get information around some restrictions beit deliberate or misconfigured. Its also an excellent way to probe what servers have blocks in place or not, ie censorship. Its also pretty much instant rerouting ie subsecond, so their ability to pass instructions to other servers in a timely manner is obvious. I wonder if their servers are using swarm intelligence in area's or not? They did custom build their own machines, which would have given them the opportunity to tear up the rule book some what.