Addressing the issue
Some of the web's biggest names are taking to day to World IPv6 Day - a 24-hour 'test' of their services run over the next generation of IP addresses.
Big names including Google, Facebook, Yahoo! and Microsoft (on its Bing search engine) are involved, enabling IPv6-based access to their websites for the day. This isn't the first time many have tested out IPv6 compatibility - Google has had an IPv6 subdomain for a while now - but it is the first time so many influential companies have thrown their consolidated weight behind promoting IPv6.
The purpose of today's 'test' is the promotion of the forthcoming exhaustion of the IPv4 address space, of which an estimated 80 million addresses, out of the 4.3 billion available, remain. Once these remaining addresses are used up, the transition to IPv6 will be required if any more devices are to be connected to the Internet, without re-using old IPv4 addresses.
There's no cause for panic, as the transition won't happen overnight, and for the general populous it should prove relatively seamless as general web traffic rarely uses IP addresses anyway, relying instead on DNS names, translated into IPs - a process that works just as well with IPv6 ad with IPv4. This test is about promoting the soon-to-be-required transition to IPv6, not
There's some irony in today's IPv6 test, as a large majority of web users will be unable to take part themselves as few ISPs offer support for IPv6 addresses currently. As all of the sites involved in today's test are also accessible via IPv4, that's not a problem, but it does put a dampener on the celebrations.