Comcast has blessed me with a working IPv6 connection, viz http://test-ipv6.com/:
What does it mean? It means that we're all set when some of the Internet service providers are forced to use the new IPv6 addresses when there are really no IPv4 addresses left. (That's likely to begin soon.) It also means I'm behind the curve technically. I understand IPv4, more or less, but v6 seems very different and a lot more complicated.
Comcast also upgraded us to 100 Mb/s download (from 50) without fanfare. That's nice, but I'd rather have had a 50% price cut.