In about four hours from now, the switch IPv4 to IPv6 begins on a worldwide basis. To celebrate the enabling of IPv6, the website, WorldIPv6Launch.org has a countdown clock–four hours and nine minutes as of this line–and some pertinent information about which web platforms, ISPs, and other web business will be enabling the latest Internet Protocol.

The list includes the following:

Committed ISPs:

Committed equipment manufacturers:

Web companies participating:

But what is IPv6 you ask, and why is it necessary. To address this, Google has been front and center, first conducting a Google+ Hangout that featured, among others, Vint Cerf, who discussed the reasons why the new Internet Protocol is necessary. If you missed that, fear not, because Google has also created an IPv6 information page that attempts to answer any concerns web users may have. The page also includes an explanatory video, featuring Cerf himself:

The problem is that the current Internet addressing system, IPv4, only has room for about 4 billion addresses — not nearly enough for the world’s people, let alone the devices that are online today and those that will be in the future: computers, phones, TVs, watches, fridges, cars, and so on. More than 4 billion devices already share addresses. As IPv4 runs out of free addresses, everyone will need to share.

If IPv4 gives us a little over 4 billion addresses, how many will IPv6 provide? The answer is more. A lot more. Try 340 trillion trillion trillion, something Google is nice enough to put in a numeric format, just to drive the extra space IPv6 creates home:

340,000,000,000,000,000,000,000,000,000,000,000,000

That’s a lot of IP addresses for us to use and abuse, or, as Google puts it, “that’s a number big enough to give everyone on Earth their own list of billions of IP addresses.” With that in mind, the changeover from 4 to 6 only makes sense, especially when you consider just how many people currently access the Internet, even more so when you consider the future generations who will soon be connected.

For the SEOs out there worrying whether or not the changeover is going to ruin years and years of work, Matt Cutts has you in mind:

Any thoughts or fears you may have about the impending IPv6 changeover?