[marksomnian]

I believe http://go isn’t special cased, but instead (ab)uses DNS search domains - the server is actually something like go.corp.google.com, and all Google PCs are configured to use corp.google.com as a search domain

[Animats]

That's normal DNS behavior. If your machine is foo15241.corp.google.com, and you ask DNS for "go", you are supposed to get "go.corp.google.com".