FWIW I suspect that by running 8.8.8.8, Google get a lot more positive value out of direct visibility of the relative popularity of domains, and common typos, t

FWIW I suspect that by running 8.8.8.8, Google get a lot more positive value out of direct visibility of the relative popularity of domains, and common typos, than anything else. Some ISP DNS services do use NXDOMAINs for search ("Did you mean ...") ... but DNS can't cope with multiple words and it's not very useful for general search. Meanwhile, anonymized query data can be used to rank domains, by location, time of day, and all sorts of things. All of which seems like very useful data when you run a search engine and ads business.