Wednesday marks the launch of a new era for the Internet — the switch to IPv6.

Great, you say. What does that mean?

In really simple terms, it means that the Internet is expanding its address directory. Right now, there are 4.3 billion IP (internet protocol) addresses on the Internet, meaning that there’s a unique address for 4.3 billion devices to connect to the Web. With the launch of IPv6, which assigns addresses in a new way, that number can grow — to 340 trillion, trillion trillion.

And believe it or not, we need the room.

In a video from Google, Internet pioneer and Google’s Chief Internet Evangelist Vint Cerf, points out that there are already enough mobile devices in the world to exhaust the addresses for the current system, IPv4. And device growth is moving much faster than population growth, according to a study from Ericsson Wednesday that projects that mobile device subscriptions will outnumber the world’s population within five years — 9 billion mobile subscriptions for 7.4 billion people.

Launch partners include Akamai, Comcast, Time Warner Cable, AT&T, Cisco, Facebook, Microsoft Bing, Yahoo and, of course, Google.

Most people shouldn’t see a difference in their daily Web use, though people who can only connect to the old protocol may have trouble seeing sites using only IPv6, but all the launch partners are running both protocols in parallel.

Windows Vista, Windows 7 and Mac OX X 10.7 all support IPv6 as well.

If you’re curious about whether or not your computer can use IPv6, you can head to a couple of sites to check your connection.

But mostly, you should be able to remain blissfully unaware of the tons of extra elbow room that’s just been added to the Internet.

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