Today is the day the internet is rolling out real support for IPv6. IPv6 is the new version of the Internet Protocol and expands the number of available addresses to a virtually limitless amount–340 trillion trillion trillion addresses.
The reason we need it is because we are or will soon run out of IPv4 internet addresses, which contains about 4 billion addresses.
Vint Cerf, who joined Google in 2005 as Chief Internet Evangelist at Google and also a founding father of the internet, directly related to IPv4, explains in a video why we need IPv6:
Google, Yahoo, Microsoft and other major internet companies had a test run of IPv6 day on June 8th with no glitches. Today is the day of the official roll out.
What does it mean to you as a webmaster? Not really that much. We covered the topic at IPv6 Coming: SEOs May Want To Prepare in February 2011 and also in March with IPv6 Support Coming To Google Webmaster Tools.
Forum discussion at WebmasterWorld.