Colitti said Google estimates that only 0.3% of its users have adopted IPv6. He said it was too early to determine how many of its users suffered from broken IPv6 connections; estimates prior to World IPv6 Day put IPv6 brokenness at 0.03% to 0.05% of Internet users.
Similarly, Lee said that Facebook estimates that about 0.2% of its users were able to reach the website via IPv6.
"Once the world gets to about 1% adoption [of IPv6], then this will be for real," Lee said. "That's the initial mass that you need to have for global adoption."
Content providers are migrating to IPv6 because the Internet is running out of addresses using IPv4. The free pool of unassigned IPv4 addresses expired in February, and in April the Asia Pacific region ran out of all but a few IPv4 addresses being held in reserve for startups. The American Registry for Internet Numbers (ARIN), which doles out IP addresses to network operators in North America, says it will deplete its supply of IPv4 addresses this fall.
IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet, but IPv6 uses 128-bit addresses and can connect up a virtually unlimited number of devices: 2 to the 128th power. IPv6 offers the promise of faster, less-costly Internet services than the alternative, which is to extend the life of IPv4 using network address translation (NAT) devices.
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