Here are a bunch more, including measurements from CDNs, ISPs, network exchanges, RIRs, the US government, and other large content providers, as well as analysis of publicly available information like AS tables, DNS records, Alexa lists: http://www.worldipv6launch.org/measurements/ http://bgp.he.net/ipv6-progress-report.cgi

My own personal measurements support these claims. I worked on a small academic conference website not too long ago and the percentage of signups from IPv6 addresses approximately matched the traffic % that Google published for that time period. My own website statistics see a higher level of IPv6 traffic than Google shows, though it caters to a more technical crowd so I am not surprised.

10% global IPv6 deployment is not a Google conspiracy. =)

Quote :

These measurements show that in a large set of 1:1 individual comparisons where the IPv4 and IPv6 paths between the same two dual stack endpoints are compared, the two protocols, as measured by the TCP SYN round trip time, are roughly equivalent. The measurements are within 10ms of each other 60% of the time.

While the connection performance is roughly equivalent once the connection is established, the probability of establishing the connection is not the same. The current connection failure rate for IPv4 connections was seen to be some 0.2% of all connection attempts, while the equivalent connection failure rate for unicast IPv6 is nine times higher, at 1.8% of all connection attempts.