I'll say it again then...
Google
can not track every site you visit via DNS for the following reasons...
1.
A DNS request doesnt ever contain the full url. It just contains the domain name. Fire up wireshark if you are in doubt and look at the packets yourself. The OS strips this at a lower level than the browser. Maybe that does create 'an overhead' as mentioned by the OP but its on the client machine and nowhere near as big as the 'overhead' that sending globally maybe billions of full URL DNS requests would cause.
2. The
only identifying information in the packet sent is IP address and the MAC address would be in the Ethernet layer. However
mac addresses are only visible on the local LAN* so the server cant see your own PC's. Also worth noting that changing your proxy will not affect a DNS lookup.
3.
DNS lookups are cached locally on your PC. The first time you visit
www.yoursite.com it caches the IP so when you then visit
www.yoursite.com/wp-admin it doesnt even contact the DNS server. I'd have thought enough people on here have had to do an "ipconfig /flushdns" when moving a site before to realize this.
4. They dont need to. Google has a lot more accurate data on all of us with just adsense & analytics on sites we visit & what we stick into google.com
In short, the DNS server has no way of seeing if you are just visiting or logging into a site (unless the login is on a different domain obviously).
heres a good explanation of a dns packet...
http://www.firewall.cx/networking-t...-name-system-dns/160-protocols-dns-query.html
now dont go thinking im saying google aint tracking the shit out of us cause they are. Im not defending them in any way (but I am very sceptical on the whole chrome phoning home thing). I just wanted to make it clear that saying they are tracking us with a DNS server is just plain ridiculous.
* yes i know thats "local local"