At approximately 4:00 eastern time, Operation: Payback changed its target to www.visa.com. The site was taken down within three minutes. However, it is currently operational.
WikiLeaks, the non-profit publishing company that publishes anonymously-submitted private documents and leaks, has been at the center of global controversy since it began publishing more than 250,000 U.S. State Department diplomatic cables in late November.
Several businesses that interact with WikiLeaks have pulled their services — including Amazon, MasterCard, Visa and Paypal, among others — and the online vigilante group known as Anonymous announced it is "declaring war" on those companies, asking supporters to stage attacks against them.
Operation: Payback, the Anonymous party behind the current siege of MasterCard, is using its Twitter feed to rally its troops. "Current Target: www.mastercard.com | Grab your weapons here," read several recent tweets, followed by a link to the tools necessary to take part in the attack.