More than half of the participating websites, including content providers such as YouTube and vendors such as Check Point, had such a good experience with IPv6 that they left it turned on after the trial ended.
"We started getting questions from our customers about World IPv6 Day. That was the motivation for us," said Bob Hinden, Check Point fellow. "Our IT team was pretty apprehensive ... but it turned out not to be that hard. ... For enterprises like us, I think you can turn [IPv6] on and leave it on."
Despite Check Point's experience, few of the largest websites -- including Google, Yahoo or Facebook -- left IPv6 on after World IPv6 Day ended.
Ari Keranan, an Ericsson network engineer, said he measured 30% of the Alexa Top 100 most popular websites supporting IPv6 on World IPv6 Day, but none of them retained IPv6 support on their main website addresses when the event was over.
Most of the largest websites turned off IPv6 support after the event because they still have back-office software to tweak and network testing to do before they feel comfortable running the new protocol in production mode.
"Making sure all of our back-end tools understand IPv6 is the largest effort for us," Lee said. "We also found with moving to IPv6 that there's nothing to fear. It works. It's ready to deploy. It wasn't that hard to do."
Now that popular websites have demonstrated that IPv6 works, the Internet engineering community is coming to the conclusion that the main problem facing IPv6 deployment isn't a lack of content, but a lack of users to view it.
Despite the success of World IPv6 Day, the vast majority of Internet traffic -- 99.98% -- remains on IPv4. And that reality makes it difficult for content providers to justify spending engineering time and dollars on IPv6 until the new standard represents at least 1% of all Internet traffic.
Consider the experience of Microsoft, which enabled IPv6 on three websites -- www.bing.com, www.xbox.com and www.microsoft.com -- for World IPv6 Day. Christopher Palmer, an engineer in Microsoft's Windows Networking area, said IPv6 users represented 0.46% of the visitors on these websites.
"IPv6 was easier than we expected. ... Our [content delivery network] really delivered," Palmer said. But he emphasized that Microsoft saw less than 0.5% of its users with IPv6 enabled. "Two million IPv6 users -- that's not scale. ... We really need to get to 1% of traffic.''