It's the percentage of IPv6 adoption seen coming from Google Fiber networks by the companies participating in the World IPv6 Launch measurements program. (See t

It's the percentage of IPv6 adoption seen coming from Google Fiber networks by the companies participating in the World IPv6 Launch measurements program. (See the bottom of http://www.worldipv6launch.org/measurements/ http://www.worldipv6launch.org/measurements/ for how IPv6 adoption rates are being measured.) My guess would be that while all Google Fiber customers very well may have IPv6, they may be using some devices that are only IPv4 capable.