Yes: Gmail (IMAP and SMTP), Google Chat (XMPP), etc. Try it out...do the DNS lookups yourself from different places.
So, it's only Google doing it?
FTP? Smtp? Distributed file shares? SQL server mirrors? NNTP? Ntp? I could probably list a dozen more.
Yes, that's a list of common internet protocols. I do not know of any example of anyone actually using geolocated DNS to CDN them. Do you have a concrete example?
Because it works, and there is more out there than just HTTP. This same approach will work for any protocol that uses DNS to resolve domain names.
Except that this is only used for HTTP. I do not know of any non-HTTP examples.
Living on Earth may be expensive, but it includes an annual free trip around the Sun.