SEO Tip #118: How is Google Public DNS Data Used?
Is Google public DNS tracking all the websites we visit while using it? Google is going to get a heck of a lot of data.
Matt Cutts: As I recall they don’t track or after some very short finite period of time they either get rid of the data or minimize it very comprehensively. But the main thing to know is I believe Google public DNS has promised not to share that data with other parts of Google, specifically search quality. So search quality, the web spam team we do not have access to the Google public DNS data. So if that’s something you are worried about don’t worry about it at all.
It’s not something that can be used in the search rankings so I think they put a fair amount of work into that. So that’s not something that you need to worry about in my opinion.