Online activists in support of WikiLeaks bring down MasterCard's Web site following the credit card company's decision to block payments to the whistle-blowing site.
The U.S. government indicates WikiLeaks spokesman Julian Assange could be in legal jeopardy for disclosing classified information because he is "not a journalist."
Group that shut down MasterCard.com and PayPal forces Visa offline with a denial-of-service attack as part of its Operation Payback campaign.
Julian Assange, leader of the controversial information-sharing site, has been arrested. He's accused of sexual molestation and rape in Sweden, London police say.