The pool of remaining available IPv4 addresses is rapidly drying up - some predictions show that they could run out completely in 2010, making it so people simply will not be able to access the internet with new devices at all when the addresses run out. This makes it necessary for a new internet standard for deployment across the entirety of the web - the internet protocol version 6, or IPv6 for short.
To quote an example from Wikipedia, your average server at http://208.77.188.166/ will become something like http://[2001:0db8:85a3:08d3:1319:8a2e:0370:7348]/, which to me looks way more messy than IPv4. Although the address space for the new protocol will be 2128, I sure will hate the new addressing system. To me, they look more like MAC addresses.
Although deployment is slow, it is actually going on. Because of this, a public IPv4 <-> IPv6 gateway service is available at http://ipv6gate.sixxs.net/, along with the ability to try out IPv6 using the tools on their site.
