I think mobile networks do play a good bit of a role here. My iPhone 5s is on Verizon's LTE network and connects over IPv6 to sites. If you look at the latest

I think mobile networks do play a good bit of a role here. My iPhone 5s is on Verizon's LTE network and connects over IPv6 to sites. If you look at the latest World IPv6 Launch measurements from Jan 16, you can see that 40% of the traffic that was measured coming from Verizon Wireless' network was coming over IPv6 - http://www.worldipv6launch.org/measurements/ http://www.worldipv6launch.org/measurements/ (Those measurements show the % of IPv6 traffic from various operator networks seen by Akamai, Facebook, Google and Yahoo.)