One of the problem with IPv4 is that the number of unique addresses it provides (around four billion) is inadequate to handle a scenario where almost everyone owns multiple devices that can connect to the Internet. It's not even enough to give everyone on the planet just one address.

Furthermore, the early days of IPv4 saw addresses being allocated in much larger blocks than the recipients could realistically require, and reallocation has proved problematic.

One of the characteristics of IPv6 is a hugely expanded address space - the line commonly used is that it provides more addresses then there are grains of sand on all of the world's beaches. It's hard to grasp a number as large as 3.4x10^38.

Anyway, support for IPv6 is included in the current major operating systems as well as in products from the big networking vendors.

And now Google has announced that its search engine is accessible over IPv6. If you're among the minority of Internet users with an IPv6 connection, you may search via ipv6.google.com. If you're not, don't bother clicking the link - it won't work.