"There's no doubt that U.S. ISPs have made significant progress in IPv6 in the last year," says John Brzozowski, chief architect for IPv6 and distinguished engineer with , which is halfway through its IPv6 deployment. "This is a numbers game, and raw numbers-wise, the U.S. has a big challenge because of the sheer size of our networks. We have the largest, contiguous ISPs in the world, with Comcast being the largest. It's interesting that a Romanian ISP can come out of nowhere and enable IPv6 on 15% of their infrastructure. I say good job to them. But I have thousands and thousands of devices to enable on my network. . . Here in the U.S., we have gotten a lot done in a relatively short period of time."

In terms of producing IPv6 content, no country comes close to the United States. Five of the 10 most popular Websites on the Internet are IPv6 enabled - and they are all run by U.S. companies. These Websites are Google, Facebook, YouTube, Yahoo and Wikipedia. In contrast, Chinese Web properties Baidu and QQ - ranked 5th and 9th respectively in Alexa's global Website rankings - don't support IPv6.

U.S. government Web sites also are leading the push towards IPv6. The National Institute of Standards and Technology (NIST) that 8% of the 1,517 federal Web sites that it tests weekly have turned on IPv6 support for DNS, mail and Web traffic, while another 34% of these Web sites are in the process of enabling IPv6 for these three services. While that still leaves 58% of U.S. government sites without IPv6 support, the NIST data reflects more progress than most other countries have made.

"The 42% of [U.S. government] domains that have made some progress towards IPv6 deployment is a significant accomplishment," says Doug Montgomery, manager of Internet & Scalable Systems Research at NIST's Information Technology Lab.