Peer deep into your router and you may find the internet is gurgling through a lot more doors today, with World IPv6 Day bringing the total number of individual addresses on the web to 340 trillion, trillion, trillion. The successor to IPv4, IPv6 dramatically increases the number of individual IP addresses - the individual identifiers assigned to each internet-connected device - to keep pace with the huge growth in online gadgets.
Until now, there have been 4.3bn IP addresses to go around; it sounds like a lot, but the Internet Assigned Numbers Authority (IANA) responsible for distributing them actually ran out more than a year ago. Without IPv6, there'd be a significant bottleneck to internet expansion, with more and more connected devices forced to share IPs.
Although many companies, ISPs and search engines like Google have already been supporting IPv6 for some time, today sees the technology officially and widely turned on alongside IPv4. That doesn't mean IPv6 addresses for everyone - systems and hardware like modems, routers and computers may need software upgrades or even physical replacement, depending on age - but it does pave the way for the next groundswell in connectivity.
It's not only more IP addresses that makes IPv6 better than IPv4. There's also streamlining in how addresses are assigned and connectivity recovered when networks change, along with standardization in how MAC address identifiers are handled. IPsec is also baked in, one of several improvements in overall network security. There's more on IPv6 at Wikipedia.