The world is getting ready to switch to IPv6. In truth, World IPv6 Launch is mostly symbolic, IPv6 adoption has been growing recently, but it's still a long way from being meaningful.
This won't change in a day, but it will make a lot more people more aware of the problem, the dwindling number of available IPv4 addresses, and it will also pave the way for ISPs and websites wanting to flip the switch later on.
The big reason why IPv6 is needed
is that IPv4 addresses have run out. If the internet is to develop naturally, it is going to need more unique IP addresses. IPv6 solves that.
But this alone probably won't be enough for regular users to want to adopt the new protocol. Luckily, IPv6 does have some significant advantages over IPv4 even for home users, from performance to convenience. IPv6 is backwards compatible, but it was designed to overcome many of IPv4's limitations.
Client-side IP address assignment, no need for DHCP
One interesting feature of IPv6 is that addresses can be assigned automatically and dynamically by the client device, meaning that there is no need for a DHCP server like there is with IPv4.
This means that you can plug a laptop to your local network, it will get an address prefix from any router it finds and then generate an IP for itself for that network, based on the hardware MAC address.
In practice, this means simpler routers and less overhead for managing IP attribution. It will also mean even less configuration requirements. Of course, you can still assign addresses to devices via DHCPv6. Multiple network addresses assigned to the same device
A second interesting feature is the ability to assign two or more addresses to the same device. You can thus stay connected to several networks at the same time, which is a great boon for flexibility. Apps will be able to choose the network they need or have access to and you won't have to choose between networks anymore. Encryption and IPsec built in
IPv6 also comes with greater security since it has an encryption option built in. This means that the communications will be secured at the lowest level possible, via IPsec, each packet that gets sent has to be decrypted for it to be interpreted. No more checksums, better performance
Also on the technical side, IPv6 gets rid of checksum verification. Since everything or almost everything sent via IPv6 networks has its own error-control mechanism, there was no need for one at the IP-level. This clears the overhead added by the need to do checksums at every step, leading to a more responsive and faster connection.
There are plenty of other improvements and optimizations that should, in the end, lead to more efficient and faster communications. Still, there's a long way before most of the internet traffic is carried over IPv6.