5. Microsoft
Microsoft operates two of the Internet's most popular Web sites: Windows Live, with its Bing search engine, and the Microsoft Network, also known as MSN. While Microsoft wouldn't respond to our queries about when these two sites will be IPv6 enabled, we were able to find IPv6 traffic coming from the autonomous system numbers that power these Web sites. We also found Microsoft engaged in IPv6 peering arrangements with at least nine carriers worldwide including Hurricane Electric, the Internet's leading IPv6 backbone network.
6. Wikipedia
The free online encyclopedia won't say when its main Web site will support IPv6. But Wikipedia IPv6-enabled its mail server and bug tracker application in 2008. Other miscellaneous services such as lists.wikimedia.org, svn.wikimedia.org and download.wikimedia.org also can be reached via IPv6. Back in 2006, Wikipedia briefly turned on IPv6 services but shut them down because of performance problems.
7. Twitter
Twitter wouldn't comment on its IPv6 plans. As of August 2009, 19% of Americans said they used Twitter, according to a Pew Internet Life survey. These Twitter users are more mobile than average Internet users, with 40% of them accessing the Internet via cell phones. This trend means Twitter is under the gun to provide IPv6 support before carriers such as Verizon roll out their next-generation mobile networks, which mandate IPv6 support.
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