Anonymous

The hacker group Anonymous took an unusual approach to its online activism on Wednesday, asking its thousands of members and supporters to publicly boycott PayPal, the payment Web site that it has criticized in response to the WikiLeaks incidents. The boycott was announced after 14 Anonymous members were arrested by the Federal Bureau of Investigation last week.

Anonymous outlined its grievances against PayPal in a joint letter that was signed by Anonymous and Lulz Security, another hacking group that has been responsible for dozens of attacks on companies and government Web sites over the past several months. The letter said the boycott was meant to show both of the groups’ displeasure with the latest actions by PayPal and the F.B.I.

“We encourage anyone using PayPal to immediately close their accounts and consider an alternative,” the letter said, adding that PayPal’s apparent willingness to work with the F.B.I. “should be proof enough that they don’t deserve the customers they get.” The letter continued, “They do not deserve your business, and they do not deserve your respect.”

During December 2010 last year, Anonymous members performed a distributed denial of service attack against PayPal, sporadically hampering the company’s Web site. Anonymous said the attacks were in retaliation for PayPal’s refusal to process credit card payments supporting WikiLeaks.

In Wednesday’s letter, Anonymous maintained its frustration with PayPal and its handling of WikiLeaks payments. “PayPal continues to withhold funds from WikiLeaks, a beacon of truth in these dark times,” the group wrote in the letter.

A PayPal spokesperson said the boycott was not affecting the company operations, noting via e-mail, “We haven’t seen any changes to our normal operations (including account opening and closing).”

Anonymous and LulzSec also asked people who join the boycott to share pictures of their account closures on Twitter and other Web sites.

British police said Wednesday that they had arrested a 19-year-old man who goes by the name Topiary online and is said to be the spokesman of LulzSec.

A previous version of this post misstated how long Anonymous took PayPal’s Web site offline. It was hampered during the attacks, not knocked offline.