The forces of Anonymous have taken aim at several companies who are refusing to do business with WikiLeaks. 4chan's hordes have launched distributed denial-of-service attacks against PayPal, Swiss bank PostFinance, and other sites that have hindered the whistleblowing site's operations.
A self-styled spokesman for the group calling himself "Coldblood" has said that any website that's "bowing down to government pressure" is a target. PayPal ceased processing donations to the site, and PostFinance froze WikiLeaks founder Julian Assange's account. The attacks are being performed under the Operation: Payback banner; Operation: Payback is the name the group is using in its long-running attacks on the RIAA, MPAA, and other organizations involved with anti-piracy lawsuits.
The initial attacks against PayPal were substantially ineffective; the PayPal blog was taken offline, but the main PayPal site wasn't harmed. The attacks against PostFinance, however, have resulted in the bank's website being unavailable for more than 16 hours. It remains unavailable at the time of writing. The latest target is the site of the Swedish prosecutors in Assange's sexual misconduct trial. This too appears to be offline. Twitter has also been named as a future attack target, due to its censorship of the #wikileaks hashtag.