Way back in December 2009, Google launched its Public DNS Service. It was, at the time, an experiment designed to help speed up web surfing as well at making the experience more secure. Today, Google announced on its blog site that its Public DNS service no longer qualifies as an experiment as it has grown to become the largest pubic DNS service in the world. Indeed, Google has announced that its Public DNS handles a whopping 70 billion requests a day.
In its blog post Google states:
Google Public DNS has become particularly popular for our users internationally. Today, about 70 percent of its traffic comes from outside the U.S. We’ve maintained our strong presence in North America, South America and Europe, and beefed up our presence in Asia. We've also added entirely new access points to parts of the world where we previously didn't have Google Public DNS servers, including Australia, India, Japan and Nigeria.
If you want to access Google's Public DNS service you can do so at its addresses; 18.104.22.168 (primary) and 22.214.171.124. (secondary). In June, as part of World IPv6 Day, Google announced its own IPv6 addresses. They can be accessed at 2001:4860:4860::8888 (primary) and 2001:4860:4860::8844 (secondary).