Liu also says that most ISPs, as far as he was aware, do not publish a data retention policy for DNS queries. So in that respect, Google Public DNS could actually improve online privacy to some extent.
"All-in-all, this is probably a good thing, but like most good things there are some risks," said Karl Auerbach, CTO of at InterWorking Labs, an attorney, and former member of the board of directors of ICANN, in an e-mail. "I tend to find that the risks are of low probability."
In all likelihood, the technical hurdle of DNS re-configuration will limit adoption of Google Public DNS, at least until Google takes steps to automate the switchover process or until Google decides to make its DNS service the default DNS configuration in Chrome OS, due to be released next year.
But if Google Public DNS does become popular, Google will have access to very valuable information about Internet user's online activities.
"It's a given that Google is going to mine your query stream to figure out what you're looking up and they're going to do something with that data," said Liu. "They're going to use that data. They don't do this out of the goodness of their heart."
Auerbach suggests Google could generate a very efficient real-time feed of top queries by setting up a DNS server like Google Public DNS. This would allow Google to immediately track the performance of URLs in TV ads placed by advertising clients, for example, and to quickly adjust the ad campaign based on real-time feedback. He also suggests Google could use DNS queries to learn about the search keywords submitted to competing search engines like Microsoft's Bing.
Google Public DNS could improve Google Search or other Google services, Auerbach says, by giving the company access to the "dark Internet," Web pages not referenced by external links.
Furthermore, Google's pre-fetching of data from popular domains, Auerbach observes, will make those domains faster, a potential competitive edge for the more responsive sites.
Google has made "speed matters" something of a corporate mantra.
There's even the possibility that Google Public DNS could weaken the Internet Corporation of Assigned Names and Numbers (ICANN), the organization that oversees Internet administration.
"In another regard this announcement could lead to some intriguing changes in the dynamics of Internet governance and ICANN because, with a large user base, it gives Google the ability to deploy its own top level domains," he said. "Of course those would be visible only to the users of Google's DNS. But free premium Google provided content under any of those Google TLDs would certainly be a strong attractant for more users and start a snowball effect ultimately resulting in the obviation of ICANN. It is perhaps unlikely that Google would chose to do this, but there's nothing that prevents it."
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