If you follow anything on IPv6 you likely noticed that several of the bigger Internet web companies like Google, Yahoo! and Facebook all announced support for World IPv6 Day via the Internet Society. The concept is pretty simple, these bigger web companies will enable IPv6 on their main websites - effectively adding a AAAA record for their primary web address.
Most of the current bigger players have IPv6 up and working already but are using an alternate name space to direct folks to a specific AAAA record. So, for instance, instead of http://www.google.com/ you go to http://ipv6.google.com/ - a minor thing for those in the know about IPv6. However, it makes it almost impossible to see the impact of publishing a super important fully qualified domain name space (like http://www.google.com) with a new AAAA record since only the people who already know about IPv6 and are likely technically savvy are using the alternate name space today.
So the challenge for the big boys who want to see what sort of impact publishing an AAAA record for their primary URL will be is the fact that losing any traffic impacts revenue. Because it is possible that an end user who is trying to get to Google and has a broken IPv6 connection will fail to see a webpage if Google has published a AAAA record. They might try a different search engine - say Yahoo! and if they do NOT have a AAAA record published the website will come up just fine on IPv4 assuming that is working for the end user. Lost revenue for Google. Executive types don't like that sort of thing... neither do shareholders.
So how do you solve this problem when you are a company like this? Effectively they have all gone in together and said let's all test the same day. That way if an end user is broken in regards to IPv6 connectivity they won't be able to get to Google but if they try Yahoo! the situation isn't any better. Neither company loses revenue to each other, they both might take a marginal hit but it is proportional and clearly acceptable if all parties are willing to be fair.
The interesting question is does this really impact end users at all? Is World IPv6 Day anything to really be excited about from an end user or even enterprise IT group perspective. Outside of being able to use the regular fully qualified domain name to reach a resource via IPv6 I would say no. Honestly, most organizations (actually almost all) do not fit in the category of having to worry how many millions of folks are reaching them and impacting their revenue day to day.
So, how can you best leverage IPv6 World Day? I would argue it would be a good day to already have IPv6 operationally running in your network, to have firewalls configured, routing working and end stations operational as a dual stack. If you have made it that far then IPv6 World Day means that those bigger web companies will actually get some meaningful data about IPv6, it's adoption rate and what they can do to better support it.
The end goal of all of this is to switch from "IPv6 World Day" to "IPv6 World" because the reality for the Internet is that the adoption has to happen and it needs to happen quickly. I don't have a problem with IPv6 World Day and I understand why the big web companies are doing it, I just think why wait? For everyone else there is little to nothing to lose but moving sooner rather than later. Chose the easier services like DNS and email to turn up on IPv6. Once that comfort level is there get the company website up on IPv6 too and you will be that much further ahead.