Not sure, but it could be by the end of 2011, IPv4 addresses will be no more; experts predict by that time, no available IPv4 address left to be giving out.  The NRO (Number Resource Organization) warns everyone to switch to IPv6 as soon as possible.  For who do not know about IPv4 and IPv6, IPv4 is the IP address format that you often see in your home’s router which looks like 192.168.1.0 (has four groups of numbers), and the IPv6 is a lot more complicated and it look something like this 3ffe:1900:4545:3:200:f8ff:fe21:67cf.  You can googling further for technical details on IPv4 and IPv6.  For your information, IPv4 could support 4 billion IP addresses.  According to Internetworldstats, only 25.6% of the world population is using the Internet, and yet 4 billion IP addresses are about to be out of reach.  Source.