This morning, thousands of companies and millions of websites permanently switched on the next generation of Internet Protocol, IPv6.
Among them: Google, Facebook and Yahoo, as expected, as well as ISPs in more than 100 countries and heavy hitters all over, from Akamai to Cisco to Comcast.
Here's what you need to know:
It's necessary, because we're running out of space. The last blocks of the 4.3 billion IP addresses enabled by the current Internet Protocol -- IPv4 -- were assigned in February 2011. Asia Pacific has already run out of room. Europe will run out this year. The U.S. will run out next year. Et cetera.
The Internet of Things depends on it. IPv6 provides more than 340 trillion, trillion, trillion addresses -- "an essentially unlimited number," the Internet Society reassures -- which matters when every connected home appliance and street corner will need an IP address, nevermind the billions of people still not online.
This "holiday" had to happen. We've long-known we were going to run out of addresses, but few were willing to make the first move. The best way to accomplish that? Have the most influential players do it at the same time.
The Internet will not break. See Steven Vaughan-Nichols' post on the subject.
...but the new addresses are not virgin territory anymore. If you were hoping to somehow avoid distributed denial-of-service attacks with the switch, think again.
This isn't hype; it's serious. Internet godfather Vint Cerf says it's just not technical freedom that's at stake -- it's a matter of avoiding state censorship, too.
You can test your IPv6 connectivity here. You're welcome.