Speak out against piracy and you might find your Web site crippled. "Anonymous" has continued its crusade against copyright advocates, this time taking down the U.S. Copyright Office's Web site via a DDoS attack, according to TorrentFreak.

The attack on the copyright.gov started on Wednesday at around 3 p.m. GMT, and kept the site completely down for about half an hour. Although it recovered, access on Thursday was slow.

The U.S. Copyright office is the part of the Library of Congress, which maintains the official directory of copyright records in the United States. According to its Web site, the office's mission is to "promote creativity by administering and sustaining an effective national copyright system."

A wave of DDoS attacks has been carried out by anti-copyright group "Operation Payback" since September, targeting anti-piracy groups, copyright lawyers, and copyright advocacy.

On Friday, "Anonymous" hit the RIAA's Web site. The attack came after Lime Wire shut down its LimeWire peer-to-peer service after losing a legal battle against RIAA record labels. The RIAA later added its two cents when it said that LimeWire broke the law and that there was nothing wrong with putting a stop to the service. There are still many alternatives to the file-sharing service, however.

On its Web site, Operation Payback had a simple message: "Payback is a bitch." The site actually appears to be down at the moment, though cached versions still show the group's messages.

"[W]e started with Denial of Service attacks; we started the protest of the future by targeting websites of lobbying groups and law firms that abuse copyright law. We simply will no longer be ignored," the group continued.

The Copyright Office did not immediately have a statement on the issue.