Your fifth point is the most important one for me. Once they know your DNS data they can make make very educated guesses about the rest of your internet traffic. Google knows what is hosted at the servers you are looking up.
And so does every other DNS provider so long as the pages are public and if your ISP is your DNS provider then they can directly sniff your (non-encrypted) traffic too.
But now you're adding yet another party in the mix -- Google, who already have a lot of information about your interests and habits. At the very very least, you're inviting an interested third party to have a look at your traffic.
Most of davidu's response was kind of a waste of time, but the one thing that made an impression on me was when he referred to Google as an advertising company. He's right; they're the most technologically advanced advertising company in the world.
So if this conversation was about "an unnamed technologically savvy advertising company", instead of Google, would you still be interested in giving them your DNS traffic?
So... you're saying that reputation counts for nothing? Google sort of evolved into an advertising company because of the position that they held as the most popular search engine.
Most advertising companies are companies that started out trying to be an advertising company. Most of them probably had to be cut-throat to make it out of obscurity.
This isn't to say that anyone should place blind trust in Google, but if -- as you're implying -- reputation counts for nothing, then what's the point in trying to maintain a reputation at all?
See my other reply in this thread too. You completely misinterpreted my post (or just used it as a soapbox to insert your views into the discussion). The post I was replying too said nothing about Google pulling all the information on you together. The poster seemed to be irked that your DNS provider also had access to the content of the pages you were using DNS lookups to view. I was pointing out that this is true of any DNS provider.
Google does not have a spotless track record in customer privacy issues, nor is there any reason to believe that because they're behaving in a particular way now, they'll behave the same later.
It's as simple as this: while I'm a fan of most of Google's products and services, I also think there's a point at which it's no longer smart to put all of your eggs into one internet company's basket, and I think we've reached that point.
True, but most of the records are deleted after 48 hours, meaning that they no longer exist for Google to decide to mine years later once they change their policy. Other than that, this only becomes an issue if the entire internet starts pointing their DNS queries at GoogleDNS, which I doubt will happen.
Not sure if their privacy policy lets them exercise their power fully in this field, though.
(i.e. If I go to sws.example.com which hosts a Secret Warez Stash, unless it's password-protected everyone has access to it, not just Google.)