Actually, you'd be surprised -- Comcast is leading the charge on the residential IPv6 front in the US, and Time Warner Cable isn't too far behind. Verizon, the largest carrier in the US not owned by a content company (by my back-of-napkin math), has been slower in deployment of IPv6, by contrast. (OTOH, since IPv6 is critical to LTE deployment, VZW et al have been much quicker on the uptake.)

I actually think that the content hosting folks are behind the curve here. Amazon is one of the biggest hold-outs; their IPv6 rollout has thus far been a total joke. No IPv6 for Cloudfront? No IPv6 glue for Route53 authoritative nameservers? No IPv6 on VPC, barely on EC2 at all, etc., etc. From what I've heard, the management at Amazon doesn't really care about the network behind their infrastructure; instead of investing in building a backbone that could do a better job supporting this kind of stuff -- and all kinds of inter-region applications which would be useful -- they want pretend the network doesn't exist and that nothing needs to change. It's too bad. I think we'd see more IPv6 usage if Amazon would get their act together.