When I moved this server to Rackspace in April (and blogged about it) one of the primary motivations was so I could provide IPv6 support.
Earlier this month I decided it'd be interesting to see just how many clients accessing the blog are actually using IPv6, so I grabbed this IPv6 Detector plugin, modified it a bit since the layout doesn't work well with my WP theme, and left it running there.
To be clear, I did this not to justify my decision to support IPv6 -- regardless of the results it's still important to me -- but just out of curiosity about what it would show.
After about two weeks the plugin has counted just over 6700 requests (page views), of which 99.6% are IPv4 and 0.4% are IPv6.
I was expecting the IPv6 number to be fairly low, probably in the single digit percentage, but hadn't expected it to be that low. I would assume that most non-bot accesses to my blog to be from reasonably technical people, as I usually write about technical or at least geeky topics.
I'm fairly sure there are no technical restrictions or misconfigurations on the server or my DNS that would prohibit people from accessing via IPv6 -- if anyone can see any, please let me know.
It's entirely possible there are lots of IPv6 clients behind IPv4 proxies or gateways, especially for corporate users. It's possible that adoption is higher in geographic areas that rarely access my blog. There are lots of possibilities.
However, if this does represent an accurate view of IPv6 adoption, the next year or so is going to be quite interesting as the last publicly available IPv4 addresses are used up and the scramble for usable addresses starts.