$ dig +short TXT google-public-dns-a.google.com "http://xkcd.com/1361/"
Heck, I even have it aliased as "pg" on all my systems.
dig +short TXT google-public-dns-a.google.com
by the way, the "http://xkcd..." part is the response, but since @asdafa didn't put \n\n after the command, it's appearing at the same line.
Turns out there are clever ways of (mis)using DNS features to make money. For example, your server could hijack NXDOMAIN responses and instead direct the user to a nice page that tells them that the name couldn't be resolved alongside a couple relevant advertisements.
This may actually be true, as google believe's that if you arrive faster to a website after searching on Google you will use Google more
Also, at the scale Google operates, I am not sure that DNS is that big of a resource commitment, and it may allow them to do fancy traffic routing stuff for their own services.
It is also a DNS server.