We have already seen what is IPv6 here, if you are not aware about that, it is the new version of the Internet Protocol which allows a lot more devices to connect to the Internet, easily.
What is World IPv6 Day?
This is a trial period where a number of major web sites like Google, Facebook, Mozilla, etc will provide their content on both IPv4 and IPv6. They will enable IPv6 on their main websites for 24 hours. It is a global-scale test flight of IPv6.
Why it is really necessary?
By this they can motivate organizations across the industry to prepare their services for IPv6 to ensure a successful transition as IPv4 address space runs out. IPv4 is expected to run out in 2011. By seeing Major Companies preparing for IPv6, other industry players might also ensure their systems to be prepared for the transition.
Will I be affected by this?
Not really, most of the Internet users will not be affected. Web services, Internet service providers, and OS manufacturers will update their systems to ensure Internet users enjoy uninterrupted service. Users may rarely encounter connectivity issues when visiting participating Websites, though they will be prepared for it.
If you want to know whether you will be affected or not, you can check your browser’s IPv6 Readiness using Google.