It may not be correlated, but that doesn't mean that Google isn't getting a ton of commercial benefit from this data. It's like having your own Alexa/Quantcast, but in realtime, and with much better granularity.
I agree. I also think it's fair for the provider of a public service to derive some benefit from running it. The obvious questions are: Is it ethical? Is it honest? (Google phrases it as "Don't be evil.")
In this case, if they are providing an alternative to filtering and hijacking, I see that as a really important step forward. The fact that a lot of people expected those behaviors shows just how bad the situation with DNS really is these days.
Furthermore, they tend to open source a lot of their stuff, so they don't have to be the only way to Chat, Wave, Browse, and probably eventually DNS.
Re:Google Public DNS
by jasonwatkinspdx on Thursday December 03, 2009 @06:20PM
(#975457)
And an even more biased population :/
http://www.techcrunch.com/2009/12/03/google-dns-opendns/