On February 4, the Internet Assigned Numbers Authority (IANA), assigned the last of IPv4 addresses. IPv4 has been the Internet communication protocol for 20+ years. Considering the rapid proliferation of personal computers, smartphones, networked appliances, and other connected devices around the world, it’s easy to conceive how we’ve already exhausted four billion IPv4 addresses.
IANA is responsible for the global coordination of the Domain Name System (DNS) Root, Internet Protocol (IP) addressing, and other Internet protocol resources. IPv6 has a very large address space and consists of 128 bits as compared to 32 bits in IPv4. The first test of IPv6 takes place on World IPv6 Day on June 8, 2011.
On World IPv6 Day, major web companies and other industry players will come together to enable IPv6 on their main websites for 24 hours. The goal is to motivate organizations across the industry -- Internet service providers, hardware makers, operating system vendors and web companies -- to prepare their services for IPv6 to ensure a successful transition as IPv4 address space runs out.
How will this affect users? Not much at first, according to this article: Moving to IPv6: Now for the hard part (FAQ) | Deep Tech - CNET News
That's because there will be strategies such as proxies, translation, and tunnels to help IPv4 and IPv6 get along. For example, a person at home whose ISP assigned an IPv4 address, could try to reach an IPv4-based Web site. But the route in between might require IPv6, in which case hardware would have to wrap up the IPv4 data in IPv6, deliver it to the other side, then unwrap it for delivery to the other computer. That would have to be repeated for each packet of data sent in either direction, slowing network performance and increasing complexity.Why do I worry? To find out your IPv6 readiness, use this test. Then you can worry, too.