TLD .google
From Just Solve the File Format Problem
.google is a top-level domain controlled by Google, as part of the current system where companies can get their brands delegated as TLDs on payment of a fee and ICANN approval.
Google controls a number of other TLDs in addition to this one; some of them are open to public registration, but this one seems to be used only for internal sites, and not to a great extent; most Google-related sites are still within google.com or other domains outside this TLD. (Want to find them? Just google them!)
