Engineers who created 4.3 billion Internet Protocol addresses back in 1981 probably thought that by the time we ran through all those, we'd be puttering around in flying cars. Flying cars are going to be a while, but it looks like our IP numbers are finally up: The American Registry for Internet Numbers, the group that hands out the numerical codes, says there are only 3.4 million IPv4 addresses left, and the group's president says the supply will probably dry up by summer, the Wall Street Journal reports. Major companies like Amazon and Microsoft are scooping up remaining addresses while they can, while others such as Facebook decided to bite the bullet and simply upgrade to the newer IPv6 system (IPv5 never really took hold).
It's not exactly an online End Times, as dire as it sounds: Asia depleted its supply of IPv4 addresses in 2011, Europe the following year, the Journal notes. And there's quite a bit of capacity under the newer IPv6 system—it can accommodate up to 340 undecillion (340 followed by 36 zeros) addresses. The main obstacle to upgrading right now seems to be the expense, not resistance to more advanced technology: A companywide migration can cost about 7% of the firm's annual IT budget, per research cited in the Journal. To see if your Internet connection supports IPv6 and/or check out IPv6-only websites, Slate points you toward the Test-IPv6.com site. (We haven't exactly been blindsided with this news, either.)