An Internet Protocol or IP address is a number that identifies each sender or receiver of information sent over the internet. The computer industry has been using IPv4 (Internet Protocol version 4) for these addresses since that protocol was developed. That technology is now reaching its technical limits for supporting unique Internet addresses, due in part to a large amount of growth with mobile devices including: mobile phones, notebook computers and wireless handheld devices. With IPv4 addresses running out this year, the entire Internet industry must adopt a new protocol called, IPv6. With this new protocol, there will be increased address space, which will allow many more devices and users on the Internet.

Many companies, including Yahoo!, are coming together to help motivate organizations across the industry- Internet service providers, hardware manufacturers, operating system vendors and other web companies- to prepare their services for their transition. We are committed to helping prepare our users for the day when IPv4 will no longer be supported, by giving them a chance to verify whether their systems are compatible with IPv6.