Fewer than 10% of IPv4 address remain
Anyone up for a bit of web infrastructure news? Well you're getting some anyway, because this is important. The Number Resource Organization, which is part of the backbone of the internet and represents the registration organizations that allocate IP addresses to machines, has declared that fewer than 10% of IPv4 addresses remain.
Every device connected to the web needs to have an address, so that it can be told apart from other computers and delivered the right information. IPv4 can support 4.3 billion devices, which the world is rapidly approaching - latest predictions suggest we'll hit that number sometime in March 2012. A newer version of the protocol - IPv6, which can support trillions of devices - was released in 2008, but businesses and ISPs have so far been slow to switch to it.
Awkwardly, the two sets of addresses aren't compatible. It's technically possible to get them to talk to each other, but it's cheaper and less complex to just switch fully to IPv6 - a system supported by Windows as far back as Windows 2000, and by Apple as far back as OS X 10.3 "Panther". Consumers are therefore likely to be fine for the switch, it's business users that are proving recalcitrant. (Update: David Cohen makes a good point in the comments below that broadband modems and routers running IPv4 could prove troublesome for consumers)
The EU already offers IPv6-compatible services, and Google has made a version of its search engine available on IPv6 at ipv6.google.com. If that link doesn't work for you, which is likely, it's because you're still on IPv4.